doc string the effect of `left' and `top' parameters in
tooltip-frame-parameters, the default values, and the units.
(tooltip-frame-parameters): Mention `top' and `left' in the doc
string.
(tooltip-show): Mention in the doc string the `top' and `left'
parameters in tooltip-frame-parameters, and x-max-tooltip-size.
(tooltip-start-delayed-tip): Renamed from tooltip-disable-timeout
and tooltip-add-timeout.
(tooltip-show): Set border color from faces's foreground.
(tooltip-show-help-function): If called with the same help string
as last time, do nothing.
(tooltip-help-tips): Don't set tooltip-help-message to nil.
(tooltip): New face
(tooltip-set-param): New function.
(tooltip-show): Set up color frame parameters from face `tooltip'.
Display the tooltip text in face `tooltip'.
(tooltip-gud-tips-p): Add :set to call tooltip-gud-tips-setup.
(tooltip-mode): Call tooltip-gud-tips-setup.
(tooltip-gud-tips): Use `gud-basic-call' instead of process-send-string,
so the prompt gets frobbed appropriately. Handle nil return value from
`tooltip-gud-print-command'.
