This is actually a request for the RadMap category, but that option is not listed in the "Category:" dropdownlist on this page for some reason?
The problem -- when a RadMap's marker has its tooltip visible (say, by rolling the mouse over the marker), moving the mouse over the tooltip itself does not prevent the tooltip from disappearing. Instead, when the mouse is rolled over the tooltip, the tooltip will hide itself.
This should be changed for two reasons: 1) when a user rolls over a tooltip, it means they are interested in the tooltip's content and likely do not want it to close. 2) If you have a link inside the tooltip, it can be impossible to reach it in time before the tooltip closes.
Lengthening the delay to closing is not a solution to this problem. Nor is enable click-to-open, click-to-close for the tooltip, since requiring clicks to open or close the tooltip is too time-consuming for quick scanning of tooltip (until the desired marker item is found).
Only keeping the tooltip visible when moused-over will resolve this issue. I can think of no reason to let the tooltip close when moused over.