Secret User Interfaces

Recently I've been upset with applications hiding user interfaces from me. It's quite annoying when relevant information about how to use an application is hidden until I move my mouse over a control and it transforms into something different.

First out is GMail.

Note how the left version of the user interface has no scroll bar. When moving the mouse cursor over the list of mail folders suddenly a scroll bar appears that signals that there are hidden folders to scroll to.

Then there is Facebook:

Look at this short list of online friends just waiting to be interacted with in the top image. Well by moving the cursor over the control we discover there are actually way more people to interact with, since the scroll bar is exposed. A bonus point for writing "more online friends" at the bottom of the control. A scroll bar would show it without any kind of special engineering effort.

Finally we have the PDF reader in google chrome.

Note how the top version shows absolutely no signs of zooming capabilities, then when moving the mouse to the bottom of the page it magically appears. Some weeks ago I spent over a minute trying to figure out how to zoom in a PDF document.

Bad user interfaces because of ignorance is something I understand, not everybody was meant to do that kind of work. What really annoy me about these examples are that someone actually put engineering effort into hiding the user interface from the user. If they just left the UI in the state it is in when the mouse is over it everything would be just fine.