validation of widgets doesn't work correct when Set is pressed with mouse (emacs 21.1)

[Geert Ribbers]

Hi.

When on a customization screen "Set for current session" is pressed with a
mouse and there is an error in the variable to set then the cursor doesn't
jump to the field in error and the error-message can not be read in the
minibuffer because the "button-message" is displayed there (you can find the
message in the *messages* buffer).
The only thing you notice is that the button "doesn't seem to work".
When the button is pressed with Enter then it works alright: cursor at the
field in error, error-message in mini-buffer.
In 2071 this was working correctly still!

Example: ps-paper-type, try to set a type that doesn't exist

Regards, Geert Ribbers