If it's buying more than 1 of a building without you holding a key, just press and release CTRL and Shift. This happens when you use a keyboard shortcut such as CTRL+T (to make a new tab), as the game doesn't know you released the key. Hope this helps, GemBz.
http://91.121.179.165/NRock/files1/06%20-%20This%20Cocaine%20Makes%20Me%20Feel%20Like%20Im%20On%20This%20Song.mp3
This cocaine makes me feel like I'm on this song
 "Realm Grinder"){kind=icon}
 "Streamline"){kind=icon}
 "Must Escape The Sewer"){kind=icon}
 "Music Catch 2"){kind=icon}