From Xojo Documentation

Property (As String )
aWebControl.HelpTag = newStringValue
StringValue = aWebControl.HelpTag

New in 2011r4

Supported for all project types and targets.

Text of a message displayed as a help tag (tooltip).


The tip/tag is displayed when the user places the mouse on the control and leaves it there.

Separate multiple lines with EndOfLine to have multi-line help tags.

Firefox does not support multi-line help tags.

For better compatibility, you can try embedding a Line Feed into the help text like this:

 Line 1
Line 2
Line 3


This code in the Shown event of a Button sets the help tag:

Me.HelpTag = "Save changes"