In the attached example I set the first button red, but setting the second
one green changes the first one back to the background color.

256 colors, RxMUI 42.2, AmigaOS 3.9 + BBs 1 & 2, A4000/040

Kind regards,
--
Robert A. Sisk
sisk637@...

/* $VER: DemoEBackground 1.0 (1.7.2007)
*/
App.Description='Demo'
App.Copyright ='© 2007 by Robert A. Sisk'

App.Title=word(SourceLine(1),3)
App.Base=App.Title

call AddLib 'rmh.library',0,-30
if RMH_AddLibrary('rxmui.library')>0 then do
call RMH_EasyRequest "Can't open" result,App.Title,'Exit'
signal Exit
end

App.Author=SubWord(App.Copyright,find(App.Copyright,'by')+1)
App.SingleTask=1
App.Version=SubWord(SourceLine(1),2)
App.SubWindow='MainWindow'
MainWindow.ID='Main'
MainWindow.Title=App.Title

MainWindow.Contents=MakeObj(,'VGroup',button('Button1','Button1'),button('Button\
2','Button2'))
call NewObj 'Application','App'

SigBreakB_Ctrl_C=12
BreakCSignal=2**SigBreakB_Ctrl_C

call notify 'MainWindow','CloseRequest',1,'App','ReturnID','Quit'

call set 'Button1','EBackground','2:FFFFFFFF,00000000,00000000'
call set 'Button2','EBackground','2:00000000,FFFFFFFF,00000000'

call set 'MainWindow','Open',1
if ~xGet('App','Iconified') then
if ~xGet('MainWindow','Open') then do
call MUIRequest 'App',,App.Title,'_Exit',"Can't open main window"
signal Exit
end

do forever
call NewHandle 'App','Event',BreakCSignal
if RMH_And(Event.Signals,BreakCSignal)>0 then
call Quit
interpret 'call' Event.Event
end

Quit:
Exit:
exit