Hidden interface controls that affect usability

I have no idea why some interfaces hide elements hide and leave the space they'd taken up unused.

IntelliJ does this, for example, with the icons above the project tree. There is this little target disc that moves the selection in the project tree to the file currently open in the active editor tab. You have to know the secret spot on the screen where it is hidden and if you move your mouse pointer to the void there, it magically appears.

Why? What is the rationale behind going out of your way to implement something like this?

This stupidity seems to have spread across Windows. No title bars or menus... now you can't tell what application a Window belongs to.

And you can't even bring all of an application's windows to the foreground... Microsoft makes you hover of it in the task bar and choose between indiscernible thumbnails, one at a time. WTF? If you have two Explorer windows open to copy stuff, then switch to other apps to work during the copy... you can't give focus back to Explorer and see the two windows again. You have to hover, click on a thumbnail. Now go back and hover, and click on a thumbnail... hopefully not the same one, because of course you can't tell WTF the difference between two lists of files is in a thumbnail.

And Word... the Word UI is now a clinic on abject usability failure. They have a menu bar... except WAIT! Microsoft and some users claim that those are TABS... except that it's just a row of words, looking exactly like a menu.

So now there's NO menu and no actual tabs... just a row of words. And if you go under the File "menu" (yes, File), there are a bunch of VIEW settings. And in there you can add and remove these so-called "tabs," and when you do remove one, the functionality disappears from the entire application. You're not just customizing the toolbar; you're actually disabling entire swaths of features from the application.

It's an absolute shitshow of grotesque incompetence, in a once-great product. No amount of derision for this steaming pile is too much.

I hate when applications stuff other controls (like browser tabs) into the title bar --- leaving you with no place to grab and move the window.

The irony is that we had title bars when monitors were only 640x480, yet now that they have multiplied many times in resolution, and become much bigger, UIs are somehow using the excuse of "saving space" to remove title bars and introducing even more useless whitespace.

I don't need to know that what I'm using is Edge/Chrome/Firefox any more than I need to know that what I'm using is Windows/etc.