Highlighting Twice to Delete Once with Text Based Editing?

Windows 25.1.0 (73)

When I try to text-based edit, I have this problem where I highlight text, the blue highlight follows, but then when I let go of the mouse, it doesn't highlight the text. 

I have to re-highlight the text so I can remove it. 

Getting pretty frustrating. Cleared all caches and it's still doing it. 

Does anyone else have this? And no - this is a production machine, so BETA versions NEVER get installed.