Signal fired when requesting a tooltip.
When using the method you should return true to either display the
tooltip or false when not to display the tooltip. You can decide
whether to show it or not based on the x and y values that you receive
from the method.
Note however that if keyboardMode is true x and y will be undefined.
You will also receive the Tooltip object where you can place
the contents to show in the tooltip. This is the only way to receive a
tooltip object to work with.
See Tooltip for more informtation.