The top of the content assist menu will put the items that are in your task context on top of the list, to enable quick selection via arrow keys. Once you start typing the menu will work as usual. Note that the Mylar Java Editor needs to be set as default for ".java" files (this is the only new functionality that comes from the Mylar Java editor).
Pressing the editor toolbar button with the Mylar glasses on it will enable/disable Mylar's automatic folding. This can be useful when needing to browse through the code, or copy/paste code around (since Eclipse's folding support can cause odd expansions when copying folded regions, bug 104648).
Ctrl+click on a comment that contains one of the following forms will open the bug with the given id: bug# 123, bug 123, Bug #123, Bug#123. (Note that all of these are case insensitive and can be followed by a colon or whitespace).