Tooltip can be described as a small label or text that appears next to a tool/control when the user pauses over it. The tooltip is typically a one-or-two-word text which describe what the control/view is. Tooltips are handy when a you have multiple tabs in application and user scroll through these tabs using left and right arrow keys.
Some usability guidelines for tooltip
- The tooltip text should be kept small limiting to one or two words only.
- Should not use symbols and punctuation in the tooltip text.
- Tooltip should be visible for 3-5 secs when the user hovers over a button/tool and should be turned off after that.
- Should be really useful for novice users.
- Click for a code snipplet on How to show tooltips in Symbian applications