Before, only MenuButtonPopup had an arrow. This makes it more obvious
as to whether the button will immediately do something when clicked or
if it will open a menu to choose a specific action.
This means the full rect won't be returned for SC_ToolButtonMenu if it
is used in a context where the default style doesn't expect the menu.
This is a separate commit to isolate future changes to this function.
* The filter icon was confusing since it had a 'refresh' badge instead of
'save/load/recent' type badge, and making the latter readable in a few pixels
is not feasible. Having the combo dropdown with saved filters is as intuitive
and works in-line.
* This gives us a consistent baseline to start from and ensures that any
things we don't customise and leave to defaults will still be the same
wherever we are running.
* The idea is tha this style won't change the palette and will just do
some minimal additions/changes to whatever the native style is, to
work around some rough spots.
baldurk