A question please

I have a question.
I'm wondering if there is a way for me to male a sort of button that when hit will open up a previously invisible window?
Like, sort of like a drop down thing if you were to right click but work for left click.
Sorry if this is confusing. D:
Please help
I'm wondering if there is a way for me to male a sort of button that when hit will open up a previously invisible window?
Like, sort of like a drop down thing if you were to right click but work for left click.
Sorry if this is confusing. D:
Please help