diff --git a/src/ui/MainRootWindow.qml b/src/ui/MainRootWindow.qml
index 7f51833de6d958c36d46dfdc2fbea4c26674475f..999bd2d2fff88631eb6960ff11fe373841fd1967 100644
--- a/src/ui/MainRootWindow.qml
+++ b/src/ui/MainRootWindow.qml
@@ -12,6 +12,7 @@ import QtQuick          2.11
 import QtQuick.Controls 2.4
 import QtQuick.Dialogs  1.3
 import QtQuick.Layouts  1.11
+import QtQuick.Window   2.11
 
 import QGroundControl               1.0
 import QGroundControl.Palette       1.0
@@ -23,12 +24,18 @@ import QGroundControl.FlightMap     1.0
 /// Native QML top level window
 ApplicationWindow {
     id:             mainWindow
-    width:          1280
-    height:         720
-    minimumWidth:   920
-    minimumHeight:  646
+    width:          ScreenTools.isMobile ? Screen.width  : Math.min(250 * Screen.pixelDensity, Screen.width)
+    height:         ScreenTools.isMobile ? Screen.height : Math.min(150 * Screen.pixelDensity, Screen.height)
+    minimumWidth:   ScreenTools.isMobile ? Screen.width  : Math.min(215 * Screen.pixelDensity, Screen.width)
+    minimumHeight:  ScreenTools.isMobile ? Screen.height : Math.min(120 * Screen.pixelDensity, Screen.height)
     visible:        true
 
+    Component.onCompleted: {
+        if(ScreenTools.isMobile) {
+            mainWindow.showFullScreen()
+        }
+    }
+
     readonly property real      _topBottomMargins:          ScreenTools.defaultFontPixelHeight * 0.5
     readonly property string    _mainToolbar:               QGroundControl.corePlugin.options.mainToolbarUrl
     readonly property string    _planToolbar:               QGroundControl.corePlugin.options.planToolbarUrl
@@ -287,6 +294,18 @@ ApplicationWindow {
             id:             toolbar
             anchors.fill:   parent
             source:         _mainToolbar
+            //-- Toggle Full Screen / Windowed
+            MouseArea {
+                anchors.fill:   parent
+                enabled:        !ScreenTools.isMobile
+                onDoubleClicked: {
+                    if(mainWindow.visibility === Window.Windowed) {
+                        mainWindow.showFullScreen()
+                    } else {
+                        mainWindow.showNormal()
+                    }
+                }
+            }
         }
     }
 
@@ -594,4 +613,3 @@ ApplicationWindow {
     }
 
 }
-
diff --git a/src/ui/preferences/DebugWindow.qml b/src/ui/preferences/DebugWindow.qml
index 266e5b613aae7ff577effc28138e6c5d9c425c29..c4acea063c49fcf6c16c6608d4241a081616a24c 100644
--- a/src/ui/preferences/DebugWindow.qml
+++ b/src/ui/preferences/DebugWindow.qml
@@ -242,6 +242,38 @@ Item {
             font.pointSize: 16
             font.family:    ScreenTools.normalFontFamily
         }
+        Text {
+            text:           qsTr("Desktop Available Width:")
+            color:          qgcPal.text
+            font.family:    ScreenTools.normalFontFamily
+        }
+        Text {
+            text:           Screen.desktopAvailableWidth
+            color:          qgcPal.text
+            font.family:    ScreenTools.normalFontFamily
+        }
+        Text {
+            text:           qsTr("Font Point Size 16.5")
+            color:          qgcPal.text
+            font.pointSize: 16.5
+            font.family:    ScreenTools.normalFontFamily
+        }
+        Text {
+            text:           qsTr("Desktop Available Height:")
+            color:          qgcPal.text
+            font.family:    ScreenTools.normalFontFamily
+        }
+        Text {
+            text:           Screen.desktopAvailableHeight
+            color:          qgcPal.text
+            font.family:    ScreenTools.normalFontFamily
+        }
+        Text {
+            text:           qsTr("Font Point Size 17")
+            color:          qgcPal.text
+            font.pointSize: 17
+            font.family:    ScreenTools.normalFontFamily
+        }
     }
 
     Rectangle {