Are you saying you can click the tool button and see the option list, but then can’t click any of the options?

Sounds like it could be some kind of conflict, are you getting any errors in the console?

Exactly, this is the situation. I can open and close but not clicking on the tools itself.

No I don’t see any errors.

Can I fix this be using z-index in css maybe? If yes, how can I do this?

I wouldn’t have thought it was a z-index problem if you can see the tool list once it opens.. The tools are also on top of the forum and shouldn’t be affected, normally you would have a z-index issue when something in your WP theme is over the forum.

Although it could be possible that the toolbox is inheriting some style’s from the WP themes stylesheet. Using the browsers inspector, can you see anything interfering with it CSS wise?