With VB4 or higher, you can place invisible controls-such as the standard Timer and CommonDialog or UserControls built with VB5 that have their InvisibleAtRuntime property set-directly on an MDIForm. In previous versions of VB, you could only put controls with an Align property on an MDIForm.
Because CommonDialog and Timer controls are often necessary, programmers previously had to hide “container” forms or use a PictureBox as a ToolBar and cash in on its container functionality to hide the invisible controls. This is no longer necessary, though it’s not widely known.