I found that Kdiff3 is not accessible for screenreaders. We have some blind employees that has no chance to use kdiff in our build environment (merging with mercurial).
Accessibitity support under windows is integrated into QT and has to be activated through some compiling option (I am not familar with QT). It has to do with the class QtAccessibleWidget. If the option is activated and a library is present, standard controls are accessible by default - ownerdraw elements has to be implemented.
Please can you check if it is possible to integrate accessibility support into kdiff3.