If your ExtJS TabPanel doesn't have scrolling arrows (and you do have enableTabScroll set to true), it could be because your chosen layout isn't "a fitting layout'.

Jack Slocum says:
The issue with the code is a TableLayout is not a "fitting" layout. It provides no dimensions to underlying components. Your TabPanel has no width defined, and no layout that provides a width, and so it can't calculate the scroll sizes correctly.
Can't quite figure out what happened to Jack and ExtJS, but I sure appreciate his answers more than most of the other guys.  They're well-written and to the point, and only happen when he feels like actually answering a question.  That's a relative rarity on the ExtJS boards. That is, if he posts, it's going to tell you what you haven't learned yet, not tell you to read the fantastic manual or, more common in ExtJS land, the library's source code.

I slapped width:500 in mine, and *poof*, profit.

Lots of wacky stuff in TabPanel, at least back in 2.x. If you have an id with two underscores in a row, that's apparently going to bork their id parser (which figures out tab relationships), for instance, which I found out the hard way. The way layout managers break (as with the above) with my Java-born expectations is also a pain.