Fix drawing of scrollbars, where previous contents were not drawn over. From John Ehresman.
Fix drawing of scrollbars, where previous contents were not drawn over.
From John Ehresman.

timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla,timonwong/foo_uie_wsh_panel_mod.scintilla