Can't tell the difference between the FileMaker 12 and 13 icons? Doug Alder to the rescue!
Some FileMaker developers, myself included, were disappointed that FileMaker Inc., did not alter the colour scheme of the new icon for FileMaker Pro 13. As a developer, I keep usually keep the last few versions of FileMaker Pro active on my drive. Lined up in my dock, I can’t tell which is FileMaker 12 and which is FileMaker 13 based on their icons. I also have this issue when I use Command Tab (Control Tab on Windows) to move back and forth between programs.
FileMaker Pro 13 Icon Replacement | HomeBase Software.