My KSP shortcuts
The first tow is my "serious" gaming. I have a dedicated installment for each game style (or role playing), almost a KSP for savegeame. And they are not all on the same KSP version, I have a gane on 1.4.1 (yet), some on 1.4.5, one for 1.6.1 (the KAX Challenge) and Company are being migrated to 1.6.1 as time allows (I'm personally code reviewing each add-on I'm installing on it).
The second row are for Test Beds for my Development needs (Official or Unofficial). These are the KSP versions I aiming to support directly.
The third row is for Test Beds for be using on older add-ons' versions, when I find something weird on a current one and find the need to test a older version on his natural habitat. It's also useful to play "what if" on some add'ons, I realized KJR/L work on 1.2.2 by clicking on that very icon on the screen (yeah, the smoking gun!).
The last row is for games I play (now and then - or never :D ) and are under Stream's control.
used on Weird set of issues on KSP Forum.