Ok, updates. I modded the MFT source, and obtained the Tank GUI also in Flight Mode. The only problem: when I modify the tank volume distribution, in flight mode, the volume available remains at maximum. While in VAB (Editor) mode, the volume available auto-updates. Here the modded parts code: #region GUI Display //[KSPField(isPersistant = true)] public bool dedicated = false; [KSPField(isPersistant = false, guiActiveEditor = true, [COLOR=#ff0000][B]guiActive = true[/B][/COLOR], guiName = "Show Tank"), UI_Toggle(enabledText = "Tank GUI", disabledText = "GUI")] [NonSerialized] public bool showRFGUI; private static GUIStyle unchanged; private static GUIStyle changed; private static GUIStyle greyed; private static GUIStyle overfull; public static string myToolTip = ""; private int counterTT; private Vector2 scrollPos; private void OnPartActionGuiDismiss(Part p) { if (p == part) showRFGUI = false; } [PartMessageListener(typeof(PartResourceListChanged))] private void MarkWindowDirty() { if (_myWindow == null) _myWindow = part.FindActionWindow(); if(_myWindow == null) return; _myWindow.displayDirty = true; } private UIPartActionWindow _myWindow; [PartMessageListener(typeof(PartChildAttached), relations: PartRelationship.AnyPart, scenes: GameSceneFilter.[COLOR=#ff0000][B]AnyEditorOrFlight[/B][/COLOR])] [PartMessageListener(typeof(PartChildDetached), relations: PartRelationship.AnyPart, scenes: GameSceneFilter.[COLOR=#ff0000][B]AnyEditorOrFlight[/B][/COLOR])] public void VesselAttachmentsChanged(Part childPart) { UpdateUsedBy(); } [PartMessageListener(typeof (PartEngineConfigChanged), relations: PartRelationship.AnyPart, scenes: GameSceneFilter.[COLOR=#ff0000][B]AnyEditorOrFlight[/B][/COLOR])] public void EngineConfigsChanged() { UpdateUsedBy(); } public void OnGUI() { EditorLogic editor = EditorLogic.fetch; [COLOR=#ff0000][B] //if (!HighLogic.LoadedSceneIsEditor || !editor || dedicated) {[/B] [B] // return;[/B] [B] // }[/B][/COLOR] //UpdateMixtures(); Rect screenRect; Rect tooltipRect; int posMult = 0; if (offsetGUIPos != -1) posMult = offsetGUIPos; if (editor.editorScreen == EditorLogic.EditorScreen.Actions && EditorActionGroups.Instance.GetSelectedParts ().Contains (part)) { screenRect = new Rect(430 * posMult, 365, 438, (Screen.height - 365)); tooltipRect = new Rect(430 * posMult+10, Screen.height - Input.mousePosition.y, 300, 20); } else if (showRFGUI && editor.editorScreen == EditorLogic.EditorScreen.Parts) { screenRect = new Rect((Screen.width - 8 - 430 * (posMult+1)), 365, 438, (Screen.height - 365)); tooltipRect = new Rect(Screen.width - 230 - 430 * (posMult+1), Screen.height - Input.mousePosition.y, 220, 20); } else { showRFGUI = false; return; } GUI.Label(tooltipRect, myToolTip); GUILayout.Window(part.name.GetHashCode(), screenRect, GUIWindow, "Fuel Tanks for " + part.partInfo.title); } Any suggestion is welcome!