Chapter #40. Don't Ever Make Your UI Move While a User is Trying to Use It
Only a psychopath would deliberately make their UI move, forcing users to "press and guess" as they try to tap or click controls.
The prevalence of Flash on the web in the late 1990s and early 2000s led to many designers introducing UI animation just because they could, and it's almost always a bad idea. Unfortunately, UI can and does move due to unintentional factors and users are left frustrated.
Do these scenarios feel familiar? Have you had a web page load, but the advertising elements are served from a different, slower server? As the page loads, the introduction of these ads "shunts" the page elements around, meaning that you click or tap on the wrong part of the page.
This can be solved by testing, then introducing placeholders to reserve space for slow-loading elements, preventing the page from moving as it loads.
Maybe you're operating a control in a mobile app, when a time-sensitive notification appears—just...