TIP: Mathematica: Use of For is often a hint that Map, Table, Scan, or something else more functional could be used. But don't stress over it!
Mathematica: Wolfram Workbench: Basic variable name refactoring is not supported. (Or just use the IntelliJ IDEA Plugin for Mathematica, which does variable and function renaming well.)
Mathematica: Wolfram Workbench: Sometimes the Outline view gets completely out of sync with the .m or .wl Package code
Mathematica: Wolfram Workbench: Sometimes the code syntax checking goes haywire (with red nearly everywhere) for no good reason (even when the code load and runs fine in Mathematica). WORKAROUND: Just restart Eclipse.
Mathematica: TIPS for living with the user-contributed MTools for Object-Orientation (until a vendor-supported OO solution is eventually provided)
Wolfram Workbench for Mathematica: Limitation: Using more than one '$' sign within function names blocks navigation on function usages.