I was developping using Scala, and the AndroidProguardScala plugin with the following mode:
https://stackoverflow.com/a/11084146/1287856
I upgraded my Android project from older versions of scala to a newer one, namely 2.10.0-RC3 with their awesome new IDE plugin :
I found myself unable to set breakpoints in my scala files by clicking on the column to the left of each file.
Fortunately, I found a workaround.
A workaround I just found for that was to change the order in which libraries are imported:
properties
Java build path
, Order and export