Share via

WindowStateChanged Event

Fires when the visibility state of a content window, such as the browser window or a tab, changes.


  Private Sub object_WindowStateChanged( _
  ByVal dwFlags As Long, _
  ByVal dwValidFlagsMask As Long)


  • object
    Object expression that resolves to the objects in the Applies To list.
  • dwFlags
    The flags indicating the current window state.

    • 1
      The content window is visible to the user.
    • 2
      The content window is enabled.
  • dwValidFlagsMask
    The flags indicating which flags in the dwFlags parameter value have been initialized.

    • 1
      The OLECMDIDF_WINDOWSTATE_USERVISIBLE flag can be checked.
    • 2
      The OLECMDIDF_WINDOWSTATE_ENABLED flag can be checked.

Error Codes

No return value.


WindowStateChanged is available only in Windows XP Service Pack 2 (SP2) or later.

The WindowStateChanged event is raised when the state of a content window, such as the browser window or a tab, might have changed. The following actions raise this event.

  • The browser window is minimized or restored.
  • An active tab becomes inactive.
  • An inactive tab becomes active.
  • The browser window is enabled or disabled due to a modal dialog box.

A content window is visible to the user when it is displayed to the user and can be interacted with. If tabbed browsing is enabled, the active tab (the one with focus) contains the content window. Background tabs are inactive. When tabbed browsing is disabled, the browser window displays the content window. When the browser window is minimized, the content window is not visible. This event can be used to minimize CPU usage and prolong battery life by reducing unnecessary updates to inactive windows.

Note  This event can be raised even if the state of the parameter flag values have not changed.

Applies To

InternetExplorer, WebBrowser