Yes, currently the global search bar only looks through the information contained in the accordion header for the elements in Tealium iQ. Generally we encourage very descriptive titles to make it easier to find what you're looking for.
You can also try using the Filter button to display extensions by their scope, or by labels you may have applied to them.
What were you looking for specifically?
I can probably leverage labels and filtering to come up with a reasonable management system, though it would be awfully nice if there was an advanced search option that let me search for a particular configuration value (or combination of values) being set.
Imagine how powerful it would be if I could pull up all cases where 'parameter' was set equal to 'this_value' so that I could modify or add to them.
Being able to search through the content of an extension, or any other element in Tealium iQ, would be pretty slick, and it is probably time we revisited the search bar functionality. I recommend mentioning this to your account manager as well. The more channels that requests for updates come through, the more likely those updates will be considered.