Interesting game. Now unfortunately it's held back by many flaws. First thing that is really annoying is your lack of properly spelled words. If English isn't your first language, don't shy away from running your text against a spell checker.

Second rather annoying issue is how when you open building UI you still may click on other buildings and open their UI's. This is rather annoying if what I want to do is click a button.

Last but not least some sort of effect would be nice whenever building has a salary to be collected. Just a little effect or icon on top of building sprite would go a long way.