musescore/MuseScore — pull request #346 by mgavioli (2013-05-11 15:31:36+00:00)
Title: Fix #21040: "View | Synth" menu item check not synched with synth window visibility

Fix #21040: closing the Synth Control window with its own close button leaves the "View | Synth" menu item checked.

Fixed by connecting SynthControl::closeEvent() with the relevant action's setChecked()