For some web elements, timing may be important
For some common web elements (like dropdowns, flyouts, or ads) there is a timing component to your testing. Often they are available for a short period of time after you move off of them. This allows people who might have shaky hands to still use those controls. But how long is long enough? Or too long? When you think about your testing for these seemingly simple elements, think about the timing and make sure you're calibrated correctly for your target audience.