Improve qubemanager Toolbar on smaller screens

fixes: QubesOS/qubes-issues#7255

qubesmanager/utils.py

@@ -104,6 +104,16 @@ def valueFromText(self, text: str) -> int:
         return int(float(value) * multiplier)
 
 
+class QubeManagerToolBar(QtWidgets.QToolBar): # pylint: disable=too-few-public-methods
+    """a toolbar that does not collapse immediately on mouse leave event"""
+    def __init__(self, parent=None):
+        super().__init__(parent)
+    def event(self, e):
+        if e.type() == QtCore.QEvent.Leave:
+            return True
+        return super().event(e)
+
+
 def get_feature(vm, feature_name, default_value):
     try:
         return vm.features.get(feature_name, default_value)
@@ -112,7 +122,7 @@ def get_feature(vm, feature_name, default_value):
 
 
 def get_boolean_feature(vm, feature_name):
-    """heper function to get a feature converted to a Bool if it does exist.
+    """helper function to get a feature converted to a Bool if it does exist.
     Necessary because of the true/false in features being coded as 1/empty
     string."""
     result = get_feature(vm, feature_name, None)

ui/qubemanager.ui

@@ -425,7 +425,7 @@ template</string>
    <addaction name="menu_view"/>
    <addaction name="menu_about"/>
   </widget>
-  <widget class="QToolBar" name="toolbar">
+  <widget class="QubeManagerToolBar" name="toolbar">
    <property name="sizePolicy">
     <sizepolicy hsizetype="Preferred" vsizetype="Preferred">
      <horstretch>0</horstretch>
@@ -1002,6 +1002,13 @@ template</string>
    </property>
   </action>
  </widget>
+ <customwidgets>
+  <customwidget>
+   <class>QubeManagerToolBar</class>
+   <extends>QToolBar</extends>
+   <header>qubesmanager/utils.h</header>
+  </customwidget>
+ </customwidgets>
  <resources>
   <include location="../resources.qrc"/>
  </resources>