RadToolTip properties ShowDelay and AutoCloseDelay control the delay in milliseconds applied to the time when the tooltip will show and hide.
ShowDelay specifies how many milliseconds should elapse before the tooltip opens starting from the moment the cursor moves over the target element (similar to the behavior of the default browser tooltip). The default setting of the ShowDelay property is 300 milliseconds.
AutoCloseDelay specifies how many milliseconds should elapse before the tooltip closes automatically if the cursor is positionedover the element (similar to the behavior of the default browser tooltip). Each movement of the mouse resets the delay, and as a result,moving over a target element without leaving its boundaries would cause the tooltip to stay visible. The default setting of the AutoCloseDelay property is 3000 milliseconds.
Set AutoCloseDelay to 0 to prevent the tooltip from hiding after an interval. If this is done the tooltip will hide only if another tooltip must be shown or if its
hide()method is called explicitly. It is similar to setting HideEvent to ManualClose but without the [x] button.