Fix small error in floating AUI frames client size under wxMSW.

The client size of the floating frames ended up being wrong because we changed
the wxRESIZE_BORDER flag after setting it and this changed it (at least under
MSW).

Reset wxRESIZE_BORDER first now and set the client size correctly afterwards.

Closes #13043.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67745 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775

src/aui/floatpane.cpp

@@ -123,7 +123,22 @@ void wxAuiFloatingFrame::SetPaneWindow(const wxAuiPaneInfo& pane)
 
     SetTitle(pane.caption);
 
-    if (pane.floating_size != wxDefaultSize)
+    // This code is slightly awkward because we need to reset wxRESIZE_BORDER
+    // before calling SetClientSize() below as doing it after setting the
+    // client size would actually change it, at least under MSW, where the
+    // total window size doesn't change and hence, as the borders size changes,
+    // the client size does change.
+    //
+    // So we must call it first but doing it generates a size event and updates
+    // pane.floating_size from inside it so we must also record its original
+    // value before doing it.
+    const bool hasFloatingSize = pane.floating_size != wxDefaultSize;
+    if (pane.IsFixed())
+    {
+        SetWindowStyleFlag(GetWindowStyleFlag() & ~wxRESIZE_BORDER);
+    }
+
+    if ( hasFloatingSize )
     {
         SetSize(pane.floating_size);
     }
@@ -144,11 +159,6 @@ void wxAuiFloatingFrame::SetPaneWindow(const wxAuiPaneInfo& pane)
 
         SetClientSize(size);
     }
-
-    if (pane.IsFixed())
-    {
-        SetWindowStyleFlag(GetWindowStyleFlag() & ~wxRESIZE_BORDER);
-    }
 }
 
 wxAuiManager* wxAuiFloatingFrame::GetOwnerManager() const