Here is an observation about potentially sluggish GUI responsiveness. (v2.0.02 compiled for Debian x86-64.)
When I open the File menu and move my pointer down to "Examples", there a very short (100ms?) delay in "Examples" being highlighed (grey background) and another short delay after that, maybe 150ms, before its sub-menu pops out on the right. This is fine.
When I move my pointer over "Effects" in the sub-menu, there is a longer delay, perhaps 300ms, before the highlighting, and again a ~150ms delay before the next sub-menu appears. This is not a significant problem.
However, when I navigate to "Reverbs", the highlighting delay is about 2 seconds, which makes the program visibly unrepsonsive, and left me wondering for that short time whether the menu system was working properly.
Placing my pointer over "MultiReverb" there is a still longer delay in the highlighting - 3 to 4 seconds - which is well outside what I expect from GUIs. Furthermore, attempting to hasten the process by clicking the "MultiReverb" text, before this time has elapsed, results in no action until the time does elapse, and then the file opens quickly. Once the time has elapsed and the word is highlighted, clicking it causes it to open quickly.
It is as if the GUI code is fighting uphill with these 3 and 4 level deep menus. I guess this is all in Juce, so there's probably nothing to be done about it, but I wanted to mention it.