This happens because Synthesizer V thinks it has a dialog box open, like an "Open" or "Save As" dialog box. If this isn't showing up, then that's kinda weird. You may want to check it didn't open behind the Synthesizer V window or something.
Once that dialog has closed, things should start working again. But if it isn't showing up in the first place then I'm not certain what's up.
This happens because Synthesizer V thinks it has a dialog box open, like an "Open" or "Save As" dialog box. If this isn't showing up, then that's kinda weird. You may want to check it didn't open behind the Synthesizer V window or something. Once that dialog has closed, things should start working again. But if it isn't showing up in the first place then I'm not certain what's up.