Better integrate with internal Qt toolbar visibility state

Closes #1583

Signed-off-by: falkTX <falktx@falktx.com>

resources/ui/carla_host.ui

@@ -571,7 +571,7 @@
   </widget>
   <widget class="QToolBar" name="toolBar">
    <property name="windowTitle">
-    <string>toolBar</string>
+    <string>Tool Bar</string>
    </property>
    <property name="movable">
     <bool>false</bool>

source/frontend/carla_host.py

@@ -542,6 +542,7 @@ class HostWindow(QMainWindow):
         self.ui.keyboard.noteOff.connect(self.slot_noteOff)
 
         self.ui.tabWidget.currentChanged.connect(self.slot_tabChanged)
+        self.ui.toolBar.visibilityChanged.connect(self.slot_toolbarVisibilityChanged)
 
         if withCanvas:
             self.ui.act_canvas_show_internal.triggered.connect(self.slot_canvasShowInternal)
@@ -1919,8 +1920,10 @@ class HostWindow(QMainWindow):
 
             showToolbar = settings.value("ShowToolbar", True, bool)
             self.ui.act_settings_show_toolbar.setChecked(showToolbar)
+            self.ui.toolBar.blockSignals(True)
             self.ui.toolBar.setEnabled(showToolbar)
             self.ui.toolBar.setVisible(showToolbar)
+            self.ui.toolBar.blockSignals(False)
 
             #if settings.contains("SplitterState"):
                 #self.ui.splitter.restoreState(settings.value("SplitterState", b""))
@@ -2035,8 +2038,10 @@ class HostWindow(QMainWindow):
 
     @pyqtSlot(bool)
     def slot_showToolbar(self, yesNo):
+        self.ui.toolBar.blockSignals(True)
         self.ui.toolBar.setEnabled(yesNo)
         self.ui.toolBar.setVisible(yesNo)
+        self.ui.toolBar.blockSignals(False)
 
     @pyqtSlot(bool)
     def slot_showCanvasMeters(self, yesNo):
@@ -2472,6 +2477,13 @@ class HostWindow(QMainWindow):
     # --------------------------------------------------------------------------------------------------------
     # Misc
 
+    @pyqtSlot(bool)
+    def slot_toolbarVisibilityChanged(self, visible):
+        self.ui.toolBar.blockSignals(True)
+        self.ui.toolBar.setEnabled(visible)
+        self.ui.toolBar.blockSignals(False)
+        self.ui.act_settings_show_toolbar.setChecked(visible)
+
     @pyqtSlot(int)
     def slot_tabChanged(self, index):
         if index != 1: