VST3 Host – not receiving all keystrokes from plug-in

Hi Everyone

Windows 10, 64 bit. vst-sdk 3.7.2

I have written a VST3 host and having issues with receiving keystrokes from plug-ins. I need to receive them so that I can pass on unused keystrokes to the main host window.

Most of the time it works. My VST3 editor container window receives WM_KEYUP and WM_KEYDOWN messages and I call the corresponding IPlugView::onKeyDown() and IPlugView::onKeyUp().

But depending on the plug-in, my container window sometimes does not receive those messages. I have checked with Spy++ and the WM_KEYUP and WM_KEYDOWN messages are being sent directly to the plug-in window.

This occurs with one plug-in in particular (there may be others), NI Massive. However, it DOES work correctly in Cubase 11 Pro and Studio One 5. So, I am obviously not doing something correctly in my code.

Any ideas on how to process will be greatly appreciated!