All chrome (Version 41.0.2272.118 (64-bit)) extensions on OS X Yosemite (10.10.2 (14C1514)) are failing to open their menu when left clicked. Right clicks bring up the expected context menu. If you select inspect popup from the context menu then the popup will show.
I have followed the following: 1) uninstalling all extensions 2) uninstalling chrome 3) removing all chrome folders and files from ~/Library 4) re-installing chrome 5) adding a single extension
and still get the same result.
If I open an incognito window then I can get the proper behavior exactly once. Closing the incognito window and opening a new one will again allow a single left click to be registered correctly.
I have also reset the PRAM on the machine to no effect.