Here is another example.
I have a gallery and in it I placed 3 circles (Give each one a tooltip of Circle1, Circle2, Circle3, etc. In something with a text propertty this is unnecessary as you can reference that but I wanted to use shapes for my example) so each item in the gallery has 3 circles (can be anything, button shape etc etc)
Each one has an OnSelect of
Switch(
CountRows(Filter(ButtonTest,Item=ThisItem.ID)),
0, Collect(ButtonTest,{Item:ThisItem.ID, Choice:Self.Tooltip}),
RemoveIf(ButtonTest,Item=ThisItem.ID);
Collect(ButtonTest,{Item:ThisItem.ID, Choice:Self.Tooltip}))
And each one has a fill of
If(
LookUp(ButtonTest, Item=ThisItem.ID,Choice)=Self.Tooltip,
RGBA(54, 176, 75, 1),
RGBA(54, 176, 75, .2))
