Hi, I know the title is strange. When I open and focus SourceTree, the fps drop significantly, from 144 to 7/8 fps.
The operations like pulling or pushing are not slow or anything, but the whole interface and system become unstable and laggish. The mouse itself moves jerkily and it's pretty annoying.
I found a solution to my problem. It was because G-sync was enabled. The same issue was present on Spotify so I searched their community pages, and found this.
... my solution is somewhat this, I just disabled G-sync when using these two apps.
Unfortunately Blueblau's answer didn't work for me. What's more is my entire development suite was behaving this way. This is what ended up fixing it for me:
1) Close the applications having issues.
2) Right click the shortcut > properties > Compatibility tab
3) Check 'Disable fullscreen optimizations'.
4) Apply > Ok > Cross your fingers and relaunch applications.
If that doesn't work, it may be worth trying to run it in compatibility mode as well. I know that's fixed some application issues I've had in the past.
Came here from a Google search. Fresh install and experienced this exact same issue, immediately after logging in for the first time (with Google). My SourceTree version is 3.0.17. Don't know the exact build number.
Sluggish mouse movement when application is in focus. Fine when in background. CPU isn't affected. Seems to be only the mouse cursor that is.
ASUS Nvidia GTX 1080ti
32GB Corsair Vengeance LPX DDR4-3000 DC RAM
Samsung Evo 850 500GB SSD