A very cool feature for presenting your graph/diagram is the ability to put a long text in a nodes 'data' field.
That way you can have a less cluttered diagram, and simply mouseover interesting nodes and get the text in a readable size.
However: The not-so-cool thing is that the tooltip auto-closes after a few seconds, making it impossible to read a semi-long explanation without constantly having to re-mouseover and finding your place in the text again.
I propose that the time limit is removed on node-tooltips
closed with the note:
This feature is available since yEd 3.9.