MQL5 ReferenceStandard LibraryPanels and DialogsCButtonOnMouseDown OnMouseDown The virtual handler of control "MouseDown" event handler. virtual bool OnMouseDown() Return Value true - event processed, otherwise - false. Note The "MouseDown" event occurs when left mouse button is pressed on the control. OnResize OnMouseUp CreatePressedLockingOnSetTextOnSetColorOnSetColorBackgroundOnSetColorBorderOnSetFontOnSetFontSizeOnCreateOnShowOnHideOnMoveOnResizeOnMouseDownOnMouseUp