Fix horizontal scrolling of wxPropertyGrid header

wxPropertyGridHeader associated with wxPropertyGrid has to be notified about every horizontal scroll of the grid.
New position is sent with dedicated wxEVT_PG_HSCROLL event being handled by wxPropertyGridManager which in turn scrolls the header accordingly.

See #18313.

include/wx/propgrid/manager.h

@@ -544,6 +544,7 @@ protected:
     void OnResize( wxSizeEvent& event );
     void OnPropertyGridSelect( wxPropertyGridEvent& event );
     void OnPGColDrag( wxPropertyGridEvent& event );
+    void OnPGScrollH(wxPropertyGridEvent& evt);
 
 
     wxPropertyGrid* m_pPropGrid;

include/wx/propgrid/propgrid.h

@@ -1456,7 +1456,10 @@ public:
     virtual bool SetFont( const wxFont& font ) wxOVERRIDE;
     virtual void SetExtraStyle( long exStyle ) wxOVERRIDE;
     virtual bool Reparent( wxWindowBase *newParent ) wxOVERRIDE;
-
+    virtual void ScrollWindow(int dx, int dy, const wxRect* rect) wxOVERRIDE;
+    virtual void SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
+                               int noUnitsX, int noUnitsY,
+                               int xPos, int yPos, bool noRefresh) wxOVERRIDE;
 protected:
     virtual void DoThaw() wxOVERRIDE;
 
@@ -1928,6 +1931,8 @@ protected:
                     unsigned int selFlags = wxPG_SEL_NOVALIDATE,
                     unsigned int column = 1 );
 
+    void SendEvent(wxEventType eventType, int intVal);
+
     // This function only moves focus to the wxPropertyGrid if it already
     // was on one of its child controls.
     void SetFocusOnCanvas();
@@ -2025,6 +2030,7 @@ wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_PROPGRID,
                           wxEVT_PG_COL_DRAGGING, wxPropertyGridEvent );
 wxDECLARE_EXPORTED_EVENT( WXDLLIMPEXP_PROPGRID,
                           wxEVT_PG_COL_END_DRAG, wxPropertyGridEvent );
+wxDECLARE_EVENT(wxEVT_PG_HSCROLL, wxPropertyGridEvent);
 
 #else
     enum {

src/propgrid/manager.cpp

@@ -321,7 +321,7 @@ private:
             else if ( i == colCount-1 )
             {
                 // Compensate for the internal border and scrollbar
-                int margin = pg->GetMarginWidth() + borderWidth + sbWidth;
+                int margin = borderWidth;
 
                 colWidth += margin;
                 colMinWidth += margin;
@@ -378,8 +378,12 @@ private:
             }
             else if ( evtType == wxEVT_HEADER_BEGIN_RESIZE )
             {
+                // Don't allow resizing the rightmost column
+                // (like it's not allowed for the rightmost wxPropertyGrid splitter)
+                if ( col == (int)m_page->GetColumnCount() - 1 )
+                    hcEvent->Veto();
                 // Never allow column resize if layout is static
-                if ( m_manager->HasFlag(wxPG_STATIC_SPLITTER) )
+                else if ( m_manager->HasFlag(wxPG_STATIC_SPLITTER) )
                     hcEvent->Veto();
                 // Allow application to veto dragging
                 else if ( pg->SendEvent(wxEVT_PG_COL_BEGIN_DRAG,
@@ -1936,6 +1940,7 @@ void wxPropertyGridManager::ReconnectEventHandlers(wxWindowID oldId, wxWindowID
                oldId);
         Unbind(wxEVT_PG_COL_DRAGGING, &wxPropertyGridManager::OnPGColDrag, this,
                oldId);
+        Unbind(wxEVT_PG_HSCROLL, &wxPropertyGridManager::OnPGScrollH, this, oldId);
     }
 
     if (newId != wxID_NONE)
@@ -1944,6 +1949,7 @@ void wxPropertyGridManager::ReconnectEventHandlers(wxWindowID oldId, wxWindowID
              newId);
         Bind(wxEVT_PG_COL_DRAGGING, &wxPropertyGridManager::OnPGColDrag, this,
              newId);
+        Bind(wxEVT_PG_HSCROLL, &wxPropertyGridManager::OnPGScrollH, this, newId);
     }
 }
 
@@ -1970,6 +1976,16 @@ wxPropertyGridManager::OnPGColDrag( wxPropertyGridEvent& WXUNUSED(event) )
 #endif
 }
 
+void wxPropertyGridManager::OnPGScrollH(wxPropertyGridEvent& evt)
+{
+#if wxUSE_HEADERCTRL
+    if ( m_pHeaderCtrl )
+    {
+        m_pHeaderCtrl->ScrollWindow(evt.GetInt(), 0);
+    }
+#endif // wxUSE_HEADERCTRL
+}
+
 // -----------------------------------------------------------------------
 
 void wxPropertyGridManager::OnResize( wxSizeEvent& WXUNUSED(event) )

src/propgrid/propgrid.cpp

@@ -1275,6 +1275,38 @@ bool wxPropertyGrid::Reparent( wxWindowBase *newParent )
     return res;
 }
 
+// -----------------------------------------------------------------------
+
+void wxPropertyGrid::ScrollWindow(int dx, int dy, const wxRect* rect)
+{
+    wxControl::ScrollWindow(dx, dy, rect);
+    if ( dx != 0 )
+    {
+        // Notify wxPropertyGridManager about the grid being scrolled horizontally
+        // to scroll the column header, if present.
+        SendEvent(wxEVT_PG_HSCROLL, dx);
+    }
+}
+// -----------------------------------------------------------------------
+
+void wxPropertyGrid::SetScrollbars(int pixelsPerUnitX, int pixelsPerUnitY,
+                                   int noUnitsX, int noUnitsY,
+                                   int xPos, int yPos, bool noRefresh)
+{
+    int oldX;
+    CalcUnscrolledPosition(0, 0, &oldX, NULL);
+    wxScrollHelper::SetScrollbars(pixelsPerUnitX, pixelsPerUnitY,
+                                  noUnitsX, noUnitsY, xPos, yPos, noRefresh);
+    int newX;
+    CalcUnscrolledPosition(0, 0, &newX, NULL);
+    if ( newX != oldX )
+    {
+        // Notify wxPropertyGridManager about the grid being scrolled horizontally
+        // to scroll the column header, if present.
+        SendEvent(wxEVT_PG_HSCROLL, oldX - newX);
+    }
+}
+
 // -----------------------------------------------------------------------
 // wxPropertyGrid Font and Colour Methods
 // -----------------------------------------------------------------------
@@ -4752,6 +4784,21 @@ bool wxPropertyGrid::SendEvent( int eventType, wxPGProperty* p,
     return evt.WasVetoed();
 }
 
+void wxPropertyGrid::SendEvent(wxEventType eventType, int intVal)
+{
+    wxPropertyGridEvent evt(eventType, m_eventObject->GetId());
+    evt.SetPropertyGrid(this);
+    evt.SetEventObject(m_eventObject);
+    evt.SetProperty(NULL);
+    evt.SetColumn(0);
+    evt.SetInt(intVal);
+
+    wxPropertyGridEvent* prevProcessedEvent = m_processedEvent;
+    m_processedEvent = &evt;
+    m_eventObject->HandleWindowEvent(evt);
+    m_processedEvent = prevProcessedEvent;
+}
+
 // -----------------------------------------------------------------------
 
 // Return false if should be skipped
@@ -6276,6 +6323,7 @@ wxDEFINE_EVENT( wxEVT_PG_LABEL_EDIT_ENDING, wxPropertyGridEvent );
 wxDEFINE_EVENT( wxEVT_PG_COL_BEGIN_DRAG, wxPropertyGridEvent );
 wxDEFINE_EVENT( wxEVT_PG_COL_DRAGGING, wxPropertyGridEvent );
 wxDEFINE_EVENT( wxEVT_PG_COL_END_DRAG, wxPropertyGridEvent );
+wxDEFINE_EVENT( wxEVT_PG_HSCROLL, wxPropertyGridEvent);
 
 // -----------------------------------------------------------------------