@odo in a perfect world yes, but plugins that embed their UI on a host window will always be tricky for this.
the plugin can be a bad actor and steal all keyboard input from the host, or it can rely on host to feed it events through specialized APIs like those in VST2 and VST3, or it can use regular windows/view events from the OS (which depends on host setting that up properly).

there are many ways to go about it, and every OS works differently. try to do drag&drop, things are even worse