hi.
i didn't know of a better place to ask this so I'm asking it here, my apologies in advance if this is not the right place.
So, H'm currently working on a project which utilizes two separate and completely different arduino boards. One of the is a attiny45 and the other one is esp8266. while working on this project, I always have two IDE windows open side by side. my problem is when I set an IDE to attiny45 the other one also changes to attiny45 and vise versa. this might look like something not that important, but it gets important when you have to change the code each 5 minutes and hit upload and when esp8266 has a ton of settings that reset to default if you change the board type, and then you have to change them back. So if anyone could help me with this, that'd be great 
!!!
You need to start two instances of the IDE.
Easiest probably by double-clicking the respective ino files.
2)
Little more work? Start the IDE and start it again. Success might depend on the OS (it works out of the box in Win7, in Win8 you need to select 'open in new window' if I recall correctly)
what you have suggested doesn't work for me...I'm on ubuntu by the way