Holy cow, I wrote a book!
Via the suggestion box,
wonders about the history and fate of the What's This? button.
(The same question was repeated by
an anonymous coward.)
The What's This? button (more formally known as the
contextual help caption button)
is turned on by the
WS_EX_CONTEXTHELP extended style
and takes the form of a question mark.
When the user clicks the button, the cursor changes to
an arrow with a question mark, and when the user clicks on a child window,
a WM_HELP message is delivered to that window.
As originally written, the intended response is for the window
to call the WinHelp function
with the HELP_CONTEXTPOPUP command and information
describing the location of the desired help text.
The WinHelp.exe program displays the help text in a
As a clue to how old this technology is,
you may observe that the pop-up window causes the original window
to become disabled,
and it comes with a rather sad looking shadow effect.
This was long
before the introduction of the CS_DROPSHADOW
window style or even layered windows.
To get a drop shadow effect, you had to draw it yourself.
And this was also the days of 4-bit color, so the drop shadow
effect is actually a dither.
Anyway, it wasn't long for What's This? to fall out of
favor and become replaced with HTML Help,
which in turn has taken a back seat to
Windows Vista Help.
It seems that help technologies change rather often,
and I'm not sure why.
Maybe it's because the user assistance folks are willing to
experiment with a lot of different ideas,
unashamed of abandoning their previous efforts when they fail
to pan out.
Maybe because designing a good help system is hard.
Maybe because users simply don't bother checking the help,
so it doesn't matter how good your help system is since nobody
uses it anyway.
I find it interesting that the
Help Guidelines asks the question,
"Are you using Help to fix a bad UI?"
There's even an entire section titled
Designing UI so that Help is unnecessary.
I find the guidelines interesting because they capture lessons
learned from earlier versions of Windows which violated those
Matthew calls out one particular dialog in Windows XP that
has a non-functional contextual help caption button.
Sorry about that.
It's a leftover from the days when contextual help was still
the recommended way of providing user assistance.
The contextual help was removed, but the button wasn't cleaned up.
You'll be happy to learn that the UI glitch has been fixed
in Windows Vista.