FLStudio's plugin manager is not up to date with the latest versions of the SDK.
This was taken from the page "VST 3 Locations / Format" in the SDK documentation:
[quote]
On the Windows platform a VST 3 Plug ...
For some reason I thought it was a bug with my mixer window, and then I realized it's any interact-able ui button/knob.
Anything that is on the right 1/5th portion of the screen cannot be clicked (even the ...
FLStudio: 12.2 [Build 3] - Signature Bundle - 64Bit
Audio: ASIO4ALL v2 (Sample rate (Hz) 44100 - Resampling quality 64-point sinc)
If you need more information about something write it and maybe describe it that I know what you mean.
Last ...