PRB: Backspace in ATL Subclassed CTL Causes IE to Navigate Back

• Microsoft Internet Explorer (Programming) versions 3.02, 4.0, 4.01, 4.01sp1, 5.0dp1

SYMPTOMS

When an ATL ActiveX control that subclasses an edit control is hosted in Internet Explorer, pressing the BACKSPACE key when focus is set to the Edit control causes Internet Explorer to navigate to the previous Web page. If there are no Web pages previous to the one with the control, the backspace key functions as normal.

CAUSE

When the user clicks on the subclassed control, the control is not UI Activated. This means that any accelerator keys are processed by the Internet Explorer frame. The control is never given a change to process the backspace accelerator key.

RESOLUTION

When the user clicks in the edit box, a WM_MOUSEACTIVATE message is sent to the control. When this message is received, manually activate the control by calling CComControl::InPlaceActivate(OLEIVERB_UIACTIVATE).

Here is sample code for a WM_MOUSEACTIVATE handler that calls InPlaceActivate to manually UI Activate itself:

LRESULT OnMouseActivate(UINT, WPARAM, LPARAM, BOOL&)
{
   // Manually activate the control
   InPlaceActivate(OLEIVERB_UIACTIVATE);

   return 0;
} 

STATUS

This behavior is by design.

REFERENCES

For additional information, please see the following article in the Microsoft Knowledge Base:

Q179696 PRB: Focus and Tab Issues with ATL Subclassed Edit Control

Additional query words:

Keywords : kbActiveX kbCtrl kbIE400 kbIE401 kbIE401sp1 kbIE500dp1 kbIEFAQ
Version : WINDOWS:3.02,4.0,4.01,4.01sp1,5.0dp1
Platform : WINDOWS
Issue type : kbprb