From c8f4d5e6692c843f55ac9de65ea0b8d161310b83 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Va=CC=81clav=20Slavi=CC=81k?= <vaclav@slavik.io>
Date: Thu, 18 Jun 2020 10:58:50 +0200
Subject: [PATCH] Fix MacReopenApp() in presence of hidden windows

wxOSX's wxApp::MacReopenApp() previously contained logic to unhide
hidden windows, but this code was commended out since 2013 as
problematic - it was showing windows like closed, but not yet
destroyed, non-modal dialogs.

Unfortunately while this part was commented out, the rest of the code
that handled existence of hidden windows was not, resulting in a bug
where nothing happened after clicking app icon in the Dock if the
application didn't have any visible window at the moment, but had a
"technical" hidden one, e.g. after opening and closing
wxPreferencesEditor.

Fixed by simplyfing and removing all (functionally commented-out) code
related to hidden windows. Instead, the logic is now:
1. do nothing if some window is already visible
2. restore an iconized window if there's one
3. call MacNewFile() if neither happened
---
 src/osx/carbon/app.cpp | 65 ++++++++++++++++++------------------------
 1 file changed, 27 insertions(+), 38 deletions(-)

diff --git a/src/osx/carbon/app.cpp b/src/osx/carbon/app.cpp
index 52be0397ec..72dfd06312 100644
--- a/src/osx/carbon/app.cpp
+++ b/src/osx/carbon/app.cpp
@@ -157,50 +157,39 @@ void wxApp::MacReopenApp()
     // if there is no open window -> create a new one
     // if all windows are hidden -> show the first
     // if some windows are not hidden -> do nothing
+    //
+    // Showing hidden windows is not really always a good solution, also non-modal dialogs when closed end up
+    // as hidden TLWs, so do preferences and some classes like wxTaskBarIconWindow use placeholder TLWs.
+    // We don't want to reshow those, so let's just reopen the minimized a.k.a. iconized TLWs.
 
+    wxTopLevelWindow* firstIconized = NULL;
     wxWindowList::compatibility_iterator node = wxTopLevelWindows.GetFirst();
-    if ( !node )
-    {
-        MacNewFile() ;
-    }
-    else
-    {
-        wxTopLevelWindow* firstIconized = NULL ;
-        wxTopLevelWindow* firstHidden = NULL ;
-        while (node)
-        {
-            wxTopLevelWindow* win = (wxTopLevelWindow*) node->GetData();
-            if ( !win->IsShown() )
-            {
-                // make sure we don't show 'virtual toplevel windows' like wxTaskBarIconWindow
-                if ( firstHidden == NULL && ( wxDynamicCast( win, wxFrame ) || wxDynamicCast( win, wxDialog ) ) )
-                   firstHidden = win ;
-            }
-            else if ( win->IsIconized() )
-            {
-                if ( firstIconized == NULL )
-                    firstIconized = win ;
-            }
-            else
-            {
-                // we do have a visible, non-iconized toplevelwindow -> do nothing
-                return;
-            }
 
-            node = node->GetNext();
+    while (node)
+    {
+        wxTopLevelWindow* win = (wxTopLevelWindow*) node->GetData();
+        if ( win->IsShown() )
+        {
+            // we do have a visible, non-iconized toplevelwindow -> do nothing
+            return;
+        }
+        else if ( win->IsIconized() )
+        {
+            if ( firstIconized == NULL )
+                firstIconized = win;
         }
 
-        if ( firstIconized )
-            firstIconized->Iconize( false ) ;
-        
-        // showing hidden windows is not really always a good solution, also non-modal dialogs when closed end up
-        // as hidden tlws, we don't want to reshow those, so let's just reopen the minimized a.k.a. iconized tlws
-        // unless we find a regression ...
-#if 0
-        else if ( firstHidden )
-            firstHidden->Show( true );
-#endif
+        node = node->GetNext();
     }
+
+    if ( firstIconized )
+    {
+        firstIconized->Iconize(false);
+        return;
+    }
+
+    // no window was shown, we need to create a new one
+    MacNewFile();
 }
 
 #if wxOSX_USE_COCOA_OR_IPHONE