I use the tool quite a bit and haven't had any issues yet. Unfortunately, I also don't have any ideas why you are.
Have you tried other sequences, other projects, other media?
Maybe you could try and make a new project in CC, new sequence like the other and import the same footage into the new one. Maybe it is an "import old project into new version" issue?
Just a guess.
Yep, buggy project..
New project with same and different footage works fine
Other project created in CC works fine
Imported sequence from CS6 works fine
Imported sequence from a buggy CC project into a new project causes crash on using Track Select tool
I was able to revert the project in question to CS6 via Final Cut Pro XML, also works fine (for now, at least), just have to redo some time remapping which didn't come through with XML translation, small loss
I guess i'll wait few more months before switching to PPro CC, maybe mysterious bugs will be worked out by then
Thank you for your replies!