[Q] can't sideload apks after rooting

Nexus 5, 4.4.4, dalvik runtime. Currently on cyanogenmod 11, but this problem started prior.

I rooted my phone, initially to run xposed framework. I actually got it installed and opened, but I noticed I couldn't install any modules. Uninstalled, tried to reinstall, found I couldn't sideload any apks. Cancel button works fine, but install button does not respond to touch in any way.

Everything I have tried:
Rebooting
Unrooting/reflashing stock
Rerooting
Using various apk installers/file managers. They all still bring me to the install screen where I can't push install, so they're unless
Clearing caches (dalvik, package installer)
Making sure all screen filter apps are off
Making sure all security options are correct (do not verify app, allow unknown sources)
Flashing a new Rom entirely (cyanogenmod)

I'm at a loss. Are there any options left to try that may fix this?

Unfortunately I can't post an image of the install screen because I'm still a new poster. I usually just try to install apps by navigating to them in my file manager and clicking on them. Nothing special. The install screen is the default holo one that pops up.




Welp, turns out it was Echo Lockscreen. That's a massive bummer...loved that app! Thanks Pirateghost.