Change button control colours via rule

i want to know if it is possible to change colours of a button with event driven rule?

i use javascript to set button colours, and they are set depending on the ‘Tooltip’ field.

i create a rule, and the action set’s the button control tooltip property.

this works, as i show a message to see that it has passed value correctly.

the button colour however doesn’t change

i have also tried conditional formatting on the button colour to change depending on the tooltip value, but that doesn’t work either

anyone have a solution?