Add a small padding at the bottom

Otherwise the button is very close to the list of objects.

resources/qml/Cura.qml

@@ -219,7 +219,7 @@ UM.MainWindow
                     left: toolbar.right
                     leftMargin: UM.Theme.getSize("default_margin").width
                     rightMargin: UM.Theme.getSize("default_margin").width
-                    bottomMargin: UM.Theme.getSize("thin_margin").width
+                    bottomMargin: UM.Theme.getSize("narrow_margin").height
                 }
             }
 

resources/qml/ObjectSelector.qml

@@ -17,9 +17,10 @@ Item
     {
         id: openCloseButton
         width: parent.width
-        height: contentItem.height
+        height: contentItem.height + bottomPadding
         hoverEnabled: true
         padding: 0
+        bottomPadding: UM.Theme.getSize("narrow_margin").height / 2 | 0
 
         anchors
         {