I tried to remap my keys the way vim has things set up. The first problem was that using lowercase keys (h, j, k, l, c, d) didn't work at all. I had to hold shift and use the uppercase key when setting the binding, which strangely makes the lowercase key work in the app. Unfortunately, FreeMind wasn't written with modal editing in mind, and it picks up the lowercase keystrokes even when I'm editing a node. So, if I have "D" mapped to cut/delete, typing "sweet dinosaurs" will result in "sweet " being typed, then the "d" deletes the node. If I type in all caps in the nodes, I won't stumble on any keybindings, but that's annoying and looks stupid.
Thank you for reporting the bug. I have created a bug report:
Keyboard shortcuts without modifiers and short node editor
I have reproduced the bug or quirk in Windows Vista, Java 1.6.0_20. I do not know which other Java versions and operating systems are affected.