Defer splitter calculation until next event

Windows doesn't have valid sizes in the size event

Fixes https://gitlab.com/kicad/code/kicad/-/issues/13019

common/widgets/properties_panel.cpp

@@ -89,7 +89,10 @@ PROPERTIES_PANEL::PROPERTIES_PANEL( wxWindow* aParent, EDA_BASE_FRAME* aFrame )
     Bind( wxEVT_SIZE,
           [&]( wxSizeEvent& aEvent )
           {
-              RecalculateSplitterPos();
+              CallAfter( [&]()
+                         {
+                            RecalculateSplitterPos();
+                         } );
               aEvent.Skip();
           } );
 }