BUG: MDI Child Window's "Minimize" System Menu Disabled

ID: Q110795

The information in this article applies to:

Microsoft Windows 3.1
Microsoft Windows NT 3.1

SYMPTOMS

After creating a new multiple document interface (MDI) child window in an MDI application, the child window's Minimize System menu option will be disabled after the following actions:

The MDI child window is created and in the topmost z-order.

The user accesses the MDI child window's System menu through the shortcut keys: ALT+SPACE, RIGHT ARROW.

These actions will cause the child window's System menu to appear with the Minimize menu option disabled. This behavior can be demonstrated with File Manager. From File Manager's Window menu, choose New Window. Next, press ALT+SPACE and then press the RIGHT ARROW key to bring up the new window's System menu. The Minimize option will be disabled.

NOTE: The Minimize menu item is not disabled if the System menu is accessed through the ALT+"-" (minus) shortcut key or the mouse. Also, the Minimize menu item is not disabled if the window is moved.

RESOLUTION

This problem may be avoided if the MDI parent calls GetSystemMenu() after creating the MDI child window. If the parent calls GetSystemMenu (hwndMDIChild, TRUE) for the MDI child window, the System menu is reset to the Windows default state, thus eliminating the problem.

STATUS

Microsoft has confirmed this to be a bug in Windows version 3.1 and Windows NT version 3.1.

MORE INFORMATION

Although MDI is supported, it is discouraged. New users find it complicated to understand, so Microsoft is encouraging ISVs to use SDI or greatly simplify their interfaces to act like an SDI (there are some advantages to coding using MDI).

Additional query words:

Keywords : kbMDI kbNTOS310bug kbGrpUser kbWinOS310bug kbWndw
Version : WINDOWS:3.1; winnt:3.1
Platform : WINDOWS winnt
Issue type : kbbug