Prevent solo-squelch focus from interrupting user actions; acts as temporary hold as well

src/visual/InteractiveCanvas.cpp

@@ -183,3 +183,11 @@ void InteractiveCanvas::OnMouseRightDown(wxMouseEvent& event) {
 void InteractiveCanvas::OnMouseRightReleased(wxMouseEvent& event) {
     mouseTracker.OnMouseRightReleased(event);
 }
+
+bool InteractiveCanvas::isMouseInView() {
+    return mouseTracker.mouseInView();
+}
+
+bool InteractiveCanvas::isMouseDown() {
+    return mouseTracker.mouseInView() && mouseTracker.mouseDown();
+}

src/visual/InteractiveCanvas.h

@@ -25,7 +25,9 @@ public:
     unsigned int getBandwidth();
 
     MouseTracker *getMouseTracker();
-
+    bool isMouseInView();
+    bool isMouseDown();
+    
     bool isAltDown();
     bool isCtrlDown();
     bool isShiftDown();

src/visual/WaterfallCanvas.cpp

@@ -730,6 +730,7 @@ void WaterfallCanvas::OnMouseReleased(wxMouseEvent& event) {
                 demod->run();
 
                 wxGetApp().bindDemodulator(demod);
+                DemodulatorThread::releaseSquelchLock(nullptr);
             }
 
             if (!demod) {