Make moving window prevent its active id from being stolen (#3392, #3243, #1738)

Amend 7b3d379, 615e9ae3

# Conflicts:
#	imgui.cpp
#	imgui_widgets.cpp

imgui_internal.h

@@ -1147,6 +1147,7 @@ struct ImGuiContext
     float                   ActiveIdTimer;
     bool                    ActiveIdIsJustActivated;            // Set at the time of activation for one frame
     bool                    ActiveIdAllowOverlap;               // Active widget allows another widget to steal active id (generally for overlapping widgets, but not always)
+    bool                    ActiveIdNoClearOnFocusLoss;         // Disable losing active id if the active id window gets unfocused.
     bool                    ActiveIdHasBeenPressedBefore;       // Track whether the active id led to a press (this is to allow changing between PressOnClick and PressOnRelease without pressing twice). Used by range_select branch.
     bool                    ActiveIdHasBeenEditedBefore;        // Was the value associated to the widget Edited over the course of the Active state.
     bool                    ActiveIdHasBeenEditedThisFrame;