diff --git a/docs/doxygen/overviews/xrc_format.h b/docs/doxygen/overviews/xrc_format.h
index ef77421733..f2ebf4e64c 100644
--- a/docs/doxygen/overviews/xrc_format.h
+++ b/docs/doxygen/overviews/xrc_format.h
@@ -559,7 +559,7 @@ pseudo-class.
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Page label (required).}
+     Page label (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label (default: none).}
 @row3col{selected, @ref overview_xrcformat_type_bool,
@@ -620,7 +620,7 @@ to use it.
 @row3col{default, @ref overview_xrcformat_type_bool,
      Should this button be the default button in dialog (default: 0)?}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
-     Bitmap to show on the button (required).}
+     Bitmap to show on the button (default: none).}
 @row3col{selected, @ref overview_xrcformat_type_bitmap,
      Bitmap to show when the button is selected (default: none, same as @c bitmap).}
 @row3col{focus, @ref overview_xrcformat_type_bitmap,
@@ -652,7 +652,7 @@ pseudo-class. @c ownerdrawnitem objects have the following properties:
 @beginTable
 @hdr3col{property, type, description}
 @row3col{text, @ref overview_xrcformat_type_text,
-     Item's label (required).}
+     Item's label (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Item's bitmap (default: no bitmap).}
 @endTable
@@ -678,7 +678,7 @@ Example:
 @beginTable
 @hdr3col{property, type, description}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
-     Label to display on the button (required).}
+     Label to display on the button (default: none).}
 @row3col{checked, @ref overview_xrcformat_type_bool,
      Should the button be checked/pressed initially (default: 0)?}
 @endTable
@@ -787,7 +787,7 @@ its @c notebookpage).
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Sheet page's title (required).}
+     Sheet page's title (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label (default: none, mutually exclusive with @c image).}
 @row3col{image, integer,
@@ -811,7 +811,7 @@ concatenated into a single string using a new line character between them
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
     First line of text on the button, typically the label of an action that
-    will be made when the button is pressed (required). }
+    will be made when the button is pressed (default: empty). }
 @row3col{note, @ref overview_xrcformat_type_text,
     Second line of text describing the action performed when the button is pressed (default: none).  }
 @endTable
@@ -822,7 +822,7 @@ concatenated into a single string using a new line character between them
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Label to use for the collapsible section (required).}
+     Label to use for the collapsible section (default: empty).}
 @row3col{collapsed, @ref overview_xrcformat_type_bool,
      Should the pane be collapsed initially (default: 0)?}
 @endTable
@@ -914,7 +914,7 @@ objects. If sizer child is used, it sets
 @row3col{value, @ref overview_xrcformat_type_string,
     Initial value of the control (default: empty).}
 @row3col{message, @ref overview_xrcformat_type_text,
-    Message shown to the user in wxDirDialog shown by the control (required).}
+    Message shown to the user in wxDirDialog shown by the control (default: empty).}
 @endTable
 
 
@@ -968,7 +968,7 @@ Example:
 @row3col{value, @ref overview_xrcformat_type_string,
     Initial value of the control (default: empty).}
 @row3col{message, @ref overview_xrcformat_type_text,
-    Message shown to the user in wxDirDialog shown by the control (required).}
+    Message shown to the user in wxDirDialog shown by the control (default: empty).}
 @row3col{wildcard, @ref overview_xrcformat_type_string,
     Sets the wildcard, which can contain multiple file types, for example:
     "BMP files (*.bmp)|*.bmp|GIF files (*.gif)|*.gif"
@@ -1056,9 +1056,9 @@ page.
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Label to display on the control (required).}
+     Label to display on the control (default: empty).}
 @row3col{url, @ref overview_xrcformat_type_url,
-     URL to open when the link is clicked (required).}
+     URL to open when the link is clicked (default: empty).}
 @endTable
 
 
@@ -1107,7 +1107,7 @@ its @c notebookpage).
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Sheet page's title (required).}
+     Sheet page's title (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label (default: none, mutually exclusive with @c image).}
 @row3col{image, integer,
@@ -1338,7 +1338,7 @@ pseudo-class.
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Page's title (required).}
+     Page's title (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label
      (default: none, mutually exclusive with @c image).}
@@ -1415,7 +1415,7 @@ pseudo-class (similarly to @ref xrc_wxnotebook "wxNotebook" and its
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Sheet page's title (required).}
+     Sheet page's title (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label (default: none).}
 @row3col{selected, @ref overview_xrcformat_type_bool,
@@ -1430,7 +1430,7 @@ Each @c propertysheetpage has exactly one non-toplevel window as its child.
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Label shown on the radio button (required).}
+     Label shown on the radio button (default: empty).}
 @row3col{value, @ref overview_xrcformat_type_bool,
     Initial value of the control (default: 0).}
 @endTable
@@ -1557,9 +1557,9 @@ objects have the following properties:
 @row3col{disabled, @ref overview_xrcformat_type_bool,
     Whether the button should be disabled (default: false).}
 @row3col{label, @ref overview_xrcformat_type_text,
-    Item's label (required).}
+    Item's label (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
-    Item's bitmap (required).}
+    Item's bitmap (default: none).}
 @row3col{small-bitmap, @ref overview_xrcformat_type_bitmap,
     Small bitmap (default: none).}
 @row3col{disabled-bitmap, @ref overview_xrcformat_type_bitmap,
@@ -1853,7 +1853,7 @@ No additional properties.
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Label to display on the button (required).}
+     Label to display on the button (default: empty).}
 @row3col{checked, @ref overview_xrcformat_type_bool,
      Should the button be checked/pressed initially (default: 0)?}
 @endTable
@@ -1891,7 +1891,7 @@ properties:
 @beginTable
 @hdr3col{property, type, description}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
-    Tool's bitmap (required).}
+    Tool's bitmap (default: empty).}
 @row3col{bitmap2, @ref overview_xrcformat_type_bitmap,
     Bitmap for disabled tool (default: derived from @c bitmap).}
 @row3col{label, @ref overview_xrcformat_type_text,
@@ -1979,7 +1979,7 @@ pseudo-class (similarly to @ref xrc_wxnotebook "wxNotebook" and its
 @beginTable
 @hdr3col{property, type, description}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Sheet page's title (required).}
+     Sheet page's title (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label
      (default: none, mutually exclusive with @c image).}
@@ -2020,9 +2020,9 @@ pseudo-class (similarly to @ref xrc_wxnotebook "wxNotebook" and its
 @beginTable
 @hdr3col{property, type, description}
 @row3col{depth, integer,
-     Page's depth in the labels tree (required; see below).}
+     Page's depth in the labels tree (default: 0; see below).}
 @row3col{label, @ref overview_xrcformat_type_text,
-     Sheet page's title (required).}
+     Sheet page's title (default: empty).}
 @row3col{bitmap, @ref overview_xrcformat_type_bitmap,
      Bitmap shown alongside the label (default: none, mutually exclusive with @c image).}
 @row3col{image, integer,
@@ -2312,7 +2312,7 @@ class-specific properties. All classes support the following properties:
 @beginTable
 @hdr3col{property, type, description}
 @row3col{orient, @ref overview_xrcformat_type_style,
-    Sizer orientation, "wxHORIZONTAL" or "wxVERTICAL" (required).}
+    Sizer orientation, "wxHORIZONTAL" or "wxVERTICAL" (default: wxHORIZONTAL).}
 @row3col{flag, @ref overview_xrcformat_type_style, wxWrapSizer flags (default: 0).}
 @endTable
 
diff --git a/misc/schema/xrc_schema.rnc b/misc/schema/xrc_schema.rnc
index cf6f68a656..cb2170ed96 100644
--- a/misc/schema/xrc_schema.rnc
+++ b/misc/schema/xrc_schema.rnc
@@ -76,11 +76,15 @@ start =
 #
 # (2) The other 'platform'-related issue is that it messes up cardinality of
 # properties elements. Properties can only be specified once, so the two forms
-# for describing properties are
+# for describing properties would be
 #
 #       1. element size {_, t_size }?   # optional property
 #       2. element size {_, t_size }    # required property
 #
+# (Fortunately, all XRC properties are optional, se the second case is a
+# non-issue and can be safely ignored. It is nevertheless briefly mentioned
+# below for explanatory purposes.)
+#
 # But this is problematic with 'platform', because it's reasonable (and,
 # indeed, done in the wild) to set properties differently for different
 # platforms:
@@ -111,14 +115,24 @@ start =
 #
 # But this is verbose and unreadable with the amount of properties present in
 # the schema. Instead, we use the more-forbidding version and annotate
-# properties with 'p' annotation (for "property") that has either 'r'
-# (required) or 'o' (optional) value:
+# properties with 'p' annotation (for "property") to mark these uses of * as
+# special and enable post-processing of the schema.
 #
-#       [xrc:p="o"] element checked { t_bool }*  # optional
-#       [xrc:p="r"] element label { t_text }+    # required
+# The value of the annotation is normally just "o" (for "optional" -- remember
+# that there are no required properties) to indicate optional properties.
+#
+# Since we have the annotation anyway, we take advantage of it to indicate
+# properties that are strictly speaking optional, but should almost always be
+# specified, even though they don't _have_ to be. A typical example would be
+# wxStaticText's label: it very rarely makes sense to omit it, but usually
+# doesn't. Such properties are indicated with the "important" value of the
+# annotation:
+#
+#       [xrc:p="o"] element checked { t_bool }*        # optional
+#       [xrc:p="important"] element label { t_text }*  # should be provided
 #
 # This makes it possible to implement tools that translate this schema into a
-# variant that use [B].
+# variant that uses [B].
 #
 
 toplevelObjectNode = (objectRef | builtinToplevelClasses | customClasses)
@@ -352,8 +366,9 @@ anyXMLContent =
 #
 # [xrc:p] marks properties, with two possible values:
 #
-#       [xrc:p="r"]     for required properties
-#       [xrc:p="o"]     for optional properties
+#     [xrc:p="o"]           for normal/optional properties
+#     [xrc:p="important"]   for important properties that
+#                           should almost always be set
 #
 
 
@@ -503,7 +518,7 @@ wxAuiNotebook =
 wxAuiNotebook_notebookpage =
     element object {
         attribute class  { "notebookpage" } &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element bitmap   {_, t_bitmap }* &
         [xrc:p="o"] element selected {_, t_bool }* &
         windowNode
@@ -534,7 +549,7 @@ wxBitmapButton =
         stdObjectNodeAttributes &
         stdWindowProperties &
         [xrc:p="o"] element default  {_, t_bool }* &
-        [xrc:p="r"] element bitmap   {_, t_bitmap }+ &
+        [xrc:p="important"] element bitmap {_, t_bitmap }* &
         [xrc:p="o"] element selected {_, t_bitmap }* &
         [xrc:p="o"] element focus    {_, t_bitmap }* &
         [xrc:p="o"] element disabled {_, t_bitmap }* &
@@ -556,7 +571,7 @@ wxBitmapComboBox_ownerdrawnitem =
     element object {
         attribute class  { "ownerdrawnitem" } &
         platform &
-        [xrc:p="r"] element text     {_, t_text }+ &
+        [xrc:p="important"] element text {_, t_text }* &
         [xrc:p="o"] element bitmap   {_, t_bitmap }*
     }
 
@@ -566,7 +581,7 @@ wxBitmapToggleButton =
         attribute class { "wxBitmapToggleButton" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="r"] element bitmap  {_, t_bitmap }+ &
+        [xrc:p="important"] element bitmap {_, t_bitmap }* &
         [xrc:p="o"] element checked {_, t_bool }*
     }
 
@@ -596,7 +611,7 @@ wxCheckBox =
         attribute class { "wxCheckBox" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="o"] element label   {_, t_text }* &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element checked {_, t_bool }*
     }
 
@@ -642,7 +657,7 @@ wxChoicebook_choicebookpage =
     element object {
         attribute class { "choicebookpage" } &
         platform &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"](
             element bitmap {_, t_bitmap } |
             element image  {_, t_integer }
@@ -657,7 +672,7 @@ wxCommandLinkButton =
         attribute class { "wxCommandLinkButton" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="r"] element label {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element note  {_, t_text }*
     }
 
@@ -667,7 +682,7 @@ wxCollapsiblePane =
         attribute class { "wxCollapsiblePane" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="r"] element label     {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element collapsed {_, t_bool }* &
         (wxCollapsiblePane_panewindow | objectRef)?
     }
@@ -738,7 +753,7 @@ wxDirPickerCtrl =
         stdObjectNodeAttributes &
         stdWindowProperties &
         [xrc:p="o"] element value   {_, t_string }* &
-        [xrc:p="r"] element message {_, t_text}+
+        [xrc:p="important"] element message {_, t_text}*
     }
 
 
@@ -772,7 +787,7 @@ wxFilePickerCtrl =
         stdObjectNodeAttributes &
         stdWindowProperties &
         [xrc:p="o"] element value    {_, t_string }* &
-        [xrc:p="r"] element message  {_, t_text }+ &
+        [xrc:p="important"] element message  {_, t_text }* &
         [xrc:p="o"] element wildcard {_, t_string }*
     }
 
@@ -847,8 +862,8 @@ wxHyperlinkCtrl =
         attribute class { "wxHyperlinkCtrl" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="r"] element label {_, t_text }+ &
-        [xrc:p="r"] element url   {_, t_url }+
+        [xrc:p="important"] element label {_, t_text }* &
+        [xrc:p="important"] element url   {_, t_url }*
     }
 
 
@@ -877,7 +892,7 @@ wxListbook =
 wxListbook_listbookpage =
     element object {
         attribute class { "listbookpage" } &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"](
             element bitmap {_, t_bitmap } |
             element image  {_, t_integer }
@@ -1009,7 +1024,7 @@ wxNotebook_notebookpage =
     element object {
         attribute class { "notebookpage" } &
         platform &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         (
             element bitmap {_, t_bitmap } |
             element image  {_, t_integer }
@@ -1059,7 +1074,7 @@ wxPropertySheetDialog_propertysheetpage =
     element object {
         attribute class { "propertysheetpage" } &
         platform &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element bitmap {_, t_bitmap }* &
         [xrc:p="o"] element selected {_, t_bool }* &
         windowNode
@@ -1071,7 +1086,7 @@ wxRadioButton =
         attribute class { "wxRadioButton" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="r"] element label {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element value {_, t_bool }*
     }
 
@@ -1081,7 +1096,7 @@ wxRadioBox =
         attribute class { "wxRadioBox" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="o"] element label     {_, t_text }* &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element dimension {_, t_integer }* &
         [xrc:p="o"] element selection {_, t_integer }* &
         element content {
@@ -1121,8 +1136,8 @@ wxRibbonButtonBar_button =
         stdObjectNodeAttributes &
         [xrc:p="o"] element hybrid                {_, t_bool }* &
         [xrc:p="o"] element disabled              {_, t_bool }* &
-        [xrc:p="r"] element label                 {_, t_text }+ &
-        [xrc:p="r"] element bitmap                {_, t_bitmap }+ &
+        [xrc:p="important"] element label         {_, t_text }* &
+        [xrc:p="important"] element bitmap        {_, t_bitmap }* &
         [xrc:p="o"] element small-bitmap          {_, t_bitmap }* &
         [xrc:p="o"] element disabled-bitmap       {_, t_bitmap }* &
         [xrc:p="o"] element small-disabled-bitmap {_, t_bitmap }* &
@@ -1311,7 +1326,7 @@ wxStaticBox =
         attribute class { "wxStaticBox" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="o"] element label {_, t_text }*
+        [xrc:p="important"] element label {_, t_text }*
     }
 
 
@@ -1328,7 +1343,7 @@ wxStaticText =
         attribute class { "wxStaticText" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="o"] element label {_, t_text }* &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element wrap  {_, t_dimension }*
     }
 
@@ -1356,7 +1371,7 @@ wxToggleButton =
         attribute class { "wxToggleButton" } &
         stdObjectNodeAttributes &
         stdWindowProperties &
-        [xrc:p="r"] element label   {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element checked {_, t_bool }*
     }
 
@@ -1383,7 +1398,7 @@ wxToolBar_tool =
     element object {
         attribute class { "tool" } &
         stdObjectNodeAttributes &
-        [xrc:p="r"] element bitmap   {_, t_bitmap }+ &
+        [xrc:p="important"] element bitmap {_, t_bitmap }* &
         [xrc:p="o"] element bitmap2  {_, t_bitmap }* &
         [xrc:p="o"] element label    {_, t_text }* &
         [xrc:p="o"] element tooltip  {_, t_text }* &
@@ -1411,7 +1426,7 @@ wxToolbook_toolbookpage =
     element object {
         attribute class { "toolbookpage" } &
         platform &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"](
             element bitmap {_, t_bitmap } |
             element image  {_, t_integer }
@@ -1443,8 +1458,8 @@ wxTreebook_treebookpage =
     element object {
         attribute class { "treebookpage" } &
         platform &
-        [xrc:p="r"] element depth    {_, t_integer }+ &
-        [xrc:p="r"] element label    {_, t_text }+ &
+        [xrc:p="important"] element depth {_, t_integer }* &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"](
             element bitmap {_, t_bitmap } |
             element image  {_, t_integer }
@@ -1519,7 +1534,7 @@ wxStaticBoxSizer =
         attribute class { "wxStaticBoxSizer" } &
         stdObjectNodeAttributes &
         [xrc:p="o"] element minsize {_, t_size }* &
-        [xrc:p="o"] element label   {_, t_text }* &
+        [xrc:p="important"] element label {_, t_text }* &
         [xrc:p="o"] element orient  {_, ("wxHORIZONTAL" | "wxVERTICAL") }* &
         (wxSizer_item | objectRef)*
     }
@@ -1575,7 +1590,7 @@ wxWrapSizer =
         attribute class { "wxWrapSizer" } &
         stdObjectNodeAttributes &
         [xrc:p="o"] element minsize {_, t_size }* &
-        [xrc:p="r"] element orient  {_, ("wxHORIZONTAL" | "wxVERTICAL") }+ &
+        [xrc:p="important"] element orient {_, ("wxHORIZONTAL" | "wxVERTICAL") }* &
         [xrc:p="o"] element flag    {_, t_style }* &
         (wxSizer_item | objectRef)*
     }