I've been trying to work with MadEdit since version 0.2.6 in Windows
I just downloaded the 0.2.7 (current beta) and still have a problem with the HEX editior view. This is probably something that is easy to fix for the next release to make MadEdit really usable.
In the right side column of the Hex View does not display the characters; only boxes and various control characters.
I discovered that if I click on the Tools Menu/Convert File Encoding; select an encoding (e.g. UTF-8) and click OK; then click the UNDO button to restore the content back to the original content; the right side column in the Hex View is fixed!