Posting this on behalf of a friend of mine:
The mouse kinda flickers around sporadically when the RMB is held down and moved around, as if trying to teleport back to where it started. This problem occurred when I reinstalled studio on a new harddrive. One odd change I noticed on the new install is that the ribbon toolbar doesn't show up on the start page, only appearing once I load a place. Studio version is 0.295.0.129917 on both drives.
This only happens in roblox studio, and every other program works fine. The flickering doesn't occur with the same software and drivers on my old harddrive. But the old harddrive doesn't seem to have this missing toolbar.
Things I've tried:
reinstalling mouse software, drivers, and switching out the mouse
deleting and reinstalling roblox/studio in it's entirety (appdata and all) (installer from www.roblox.com/download)
directly copying the studio files from the old harddrive
changing/disabling the DPI scaling behavior on all ROBLOX Studio processes (http://i.imgur.com/UPU2c6o.jpg) as this fixed it for other people
changing/disabling windows scaling altogether
changing hardware mouse in roblox studio settings
running studio as administrator (this breaks both roblox player and roblox studio with some strange permissions, forcing me to use an unlocking tool to delete the files and reinstall roblox)
Specs if that helps: