MacOS window refresh UI client area corruption

[whalley]

When refreshing part of a window, such as a wxTreeCtrl or wxListCtrl, especially within focus events the non-updated part the client area can be corrupted, which it makes it look as though text becomes bold and icons aren't draw correctly.

Left navigation pane is blurry/bold until it's clicked or scrolled. Scrolling "fixes" the whole list:

Seems related to this - wxWidgets/wxWidgets#22629

[whalley]

Fix identified. wxWidgets/wxWidgets#22629 (comment)

Will look to include temporary fix for now as this can be quite distracting and annoying. Will keep open until wx3.2.2 is available