%th specifies that help strings will appear in volatile rectangular boxes
adjacent to the associated control when the mouse is over the control. There is
a programmed delay before the help string appears, similar to %`bh but without
a spike. ctrl is set to 1 to make the help tooltip visible and zero to
If a grave accent modifier is used, a question mark button appears on the
caption bar of the window. When the user clicks on this button, the mouse
cursor changes to an arrow with a question mark. If the user then clicks on a
control that has help information, the above tooltip help window pops
You cannot use %th and %`th is the same window.
A window that uses %`th cannot have a maximise button or a minimise button.
The option [at_cursor] causes the tooltip to be displayed relative to
the current mouse position rather than relative to the control.
The option [no_callback_hide] prevents the tooltip from being hidden when
a callback function is called. The default action is for the tooltip to be
hidden whilst the callback is invoked.
The option [delay] allows you to set the time interval between the mouse
entering a control and a tooltip appearing. An additional integer
argument provides the delay in milliseconds. For example,
specifies a 1/2 second delay. The default is 1500ms.
The option [ms_style] provides for a Microsoft style tooltip. It also allows
you to change the tooltip text at run-time using the routine set_tooltip_text@
(see Note 10 on %di).
The option [balloon] provides a tooltip in the shape of a balloon.
When used with a grave accent, [ms_style] provides context sensitive
help with the conventional Microsoft appearance.