Operating system and graphics card
Win 7 64 Bit, Nvidia 1060
Broken: (example: 2.69.7 4b206af, see splash screen)
Seems to be around since eons
Short description of error
Holding key R for rotation flickers between trackball and rotate mode
Exact steps for others to reproduce the error
Based on a (as simple as possible) attached .blend file with minimum amount of steps
Simple as open Blender and holding down R for rotation.
You will notice that the widget and the text in the header starts to flicker between rotation and trackball navigation.
Easy fix would be to change the keymap value (or better values, since the navigation keys exists in more than one editor) from Press to Release. Then you have to release the mouse once to switch to trackball navigation. And nothing flickers anymore.