Fix StatusBar white flicker when maximizing the form (v2)

[klaus101]

The previous fix about statusbar white flash caused flicker at 'normal' resizing.

An even simplified version of the fix appears to cover this, probably because a doubled FillRect is avoided.

[zamtmn]

You change src/uwin32widgetsetdark.pas and add other copy uwin32widgetsetdark.pas to root. something wrong