Centre RGBA markers in all cases including when larger than allocation. Bug #3494184.
Centre RGBA markers in all cases including when larger than allocation. Bug #3494184.

keperlia/foo-wsh-panel-mod.scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla,keperlia/foo-wsh-panel-mod.scintilla,keperlia/foo-wsh-panel-mod.scintilla,windoze/scintilla,windoze/scintilla,keperlia/foo-wsh-panel-mod.scintilla,keperlia/foo-wsh-panel-mod.scintilla,windoze/scintilla,windoze/scintilla,windoze/scintilla,keperlia/foo-wsh-panel-mod.scintilla