A while ago, I wrote this post (Using SourceMate 3.0 to create code bookmarks). While poking around in the Flash Builder preferences, I came across some references to the Bookmarks view. It turns out, this feature has been there all along.
To show the view
Go to Window > Show View > Other… and choose General > Bookmarks. This will show the view in the bottom pane.
To add a bookmark
When on a line of code, go to Edit > Add Bookmark… By default, this does not have a shortcut key.
To add a shortcut key combo
Go to Preferences, General > Keys. Scroll down a little to Add Bookmark. In the Binding input, you can add a key combo that works for you. I’m on a Mac and alt/option+B was available and easy to remember.
It even allows you to name the bookmarks, which is nice.