Some fixes: when setting MUIA_Prop attributes check if the
new value is same as old value and if so don't refresh and
set tag to TAG_IGNORE. In OM_GET return TRUE for MUIA_Prop_Release
as TextEditor.mcc otherwise has scroll problems (when using
slider: while dragging it constantly tries to snap scroll position
to multiple of line height) because of non working notification.
MUI may handle this differently (see comment). Some other little
fixes/changes.
git-svn-id: https://svn.aros.org/svn/aros/trunk/AROS@28872 fb15a70f-31f2-0310-bbcc-cdcc74a49acc