In 4.0, they are. Sort of.
The new "volume scroller" should accomplish this. If you tap in the lower right corner, then drag up, you can select any "volume". (A volume is a Bible translation, commentary, dictionary, or other book.)
Bibles and commentaries should be "synced" I believe, so if you're reading John 1:1 in the KJV, and bring up a commentary, you should be in the same place.
Of course, "Analyze Verse" does this in an even better, more consolidated way, only using a single verse at a time. Just tap the verse number and tap "Analyze Verse."
Just as an aside -- no, analyze verse is not buggy when it comes to commentaries. It works the way it's designed. What am I talking about? Every time you use "Analyze Verse" you may get a different list of commentaries to choose from, and at first it can be confusing. What's going on is this: Analyze Verse only displays commentaries that have an entry for the current verse.
So, for example, Genesis 1:1 may have an entry for all 5 commentaries you have installed. (Every commentator has an entry for Genesis 1:1!) But move to Genesis 1:2, and only 2 commentaries may show up. The other 3 commentaries may have no entry for Genesis 1:2.