Hi, for this I think I can help...
on the toolbox actor, if you want it to be invisible from the start, you have to do this:
Create actor / Visibility State / disable.
Then on the button actor:
Mousebuttondown / script editor:
click on variables/fonctions and choose Visibility state: select the tool box actor and "enable"
then click Add and immediate action.
this should do the pop up thing.
finaly to make the toolbox invisible again:
on the toolbox, Mousebuttondown / Visibilitystate / event actor / disable.
Et voila, it's as simple as that
I hope this helps you