Example:

Code Insight will pop up just fine for the variable's name itself, like:

$ar[TAB]
$array

But it does not complete the names of keys that have already been defined elsewhere in the file/project:

$array['er[TAB]
$array['er

Many other editors are able to handle this, and I was surprised that PHPEd is not. Is this hidden in some option I do not see, or is this not in the program?

This will get you half way there: can-code-templates-be-inserted-like-autocorrect-t5019.html

Maybe, but that's hardly an ideal solution. That'd require me to set up all of them ahead of time, which is hardly worth it.

A feature like this would be great. Even just supporting the keys in the built-in arrays like $_SERVER would already be a big step forward.

[Moved to Feature Requests for PhpED]

+1.

like anno said, even if it were implemented just for the super globals, i'd be happy.

That sounds like a great idea, I wonder if it would be possible to handle keys such as $array["blah$var"]

+4 from our office