Craig try using an LED (square) behind it instead of a bitmap. I have had some success that way(0 should be easier to control with on /off of the led. In each tab page turn on the LED on open and turn OFF the led on close.
I might try that but I like DRO's better, as I can choose more colors, but without having the ability to know what group I am presently in, I can't find a way to set background colors conditionally. More testing. If I can find that, might be able to functionally use the tabbing feature.
(finding the page I'm on, I can test for, but groups within the page is alluding me)
I thought something like might work at the end of my plc script to see if values changed if I picked different items on the screen.
local t1, t2, t3 = scr.GetProperty("MainTabs", "tabProgramRun", "grpAxisAxisControl")
mc.mcCntlSetLastError(inst, 'testing = ' .. tostring(t1)..' '.. tostring(t2)..' '.. tostring(t3));
Also, tabbing scrolls thru the page buttons but have not found a way to know what button is currently active. Might be able to change the color of the button to show it has been selected using that feature (I can see the dotted lines around the button text). Interesting avenue you have sent me on again Terry.
as far as setting your led states:
try this, just replace the myled with the name you gave yours:
scr.SetProperty('myled', 'Value', '1'); --turn on
scr.SetProperty('myled', 'Value', '0'); --turn off