PRB: Property Pages Consume USER Resources When Displayed

• Microsoft OLE Control Development Kit (CDK), version 1.0

SYMPTOMS

Displaying many property pages in a frame may cause USER resources to decline significantly or can even cause a general protection (GP) fault in extreme cases.

CAUSE

The property page frame implementation causes each page to remain in memory after it is created, even after switching to another page. Because each page is usually populated with several child windows, this can cause USER resources to decrease substantially. The resources are released when the property page frame is destroyed.

STATUS

This behavior is by design and considered an efficiency optimization. A property page is essentially a modeless dialog, and it takes time to create them on demand. For this reason, as each page is selected, it is kept in memory until the entire property page frame is dismissed. Thus, if the page is re-selected, it does not have to be re-created.

RESOLUTION

There is no way to prevent this behavior, although several techniques can be used to minimize the impact:

• Use as few property pages as possible.
• Reduce the number of child windows (controls) on each page.
• Use the OLE control under Windows NT version 3.5 or later. Windows NT provides essentially unlimited USER resources to 16-bit applications.