Update progress immediately in the taskbar button sample.

Handle all scroll events instead of just wxEVT_SCROLL_CHANGED which was
probably done accidentally.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77702 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Don't crash under XP in the taskbar button sample.

Refuse to run if the taskbar button API is not available.

This wouldn't make much sense anyhow and is the simplest thing to do.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77703 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Revert "Avoid generating wxEVT_MENU_OPEN and CLOSE for disabled menus in wxMSW."

The check for top level menus being disabled added in r77657 is broken as it's
used, with the expectedly bad consequences, for non top level menus as well,
as can be seen by opening any submenu, so revert it.

See #2168.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77704 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Use factory function for wxTaskBarButton creation.

This allows to encapsulate checking for errors, which should be handled when
using this class as task bar buttons API is not available under Windows XP.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77705 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Make wxAppProgressIndicator actually usable.

First of all, do define it under non-MSW platforms.

Second, don't crash in it when running under XP where wxTaskBarButton is not
available.

Also add IsAvailable() method to check for its availability explicitly and add
a demonstration of this class to the dialogs sample.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77706 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775
Always include wxGA_PROGRESS in wxGauge styles enumeration.

It can still be used even if it's not available under the current platform.

git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@77707 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775