Simpson, I hit this issue myself when upgrading to 0.026. In my case it turned out that the screen set I was using, which is one I customized, not the one supplied in 0.026, didn't have the format strings set correctly for the offset entry/display windows. After the % char in the format string there should be a + symbol, it wasn't there in my screen set. Putting it back in (using screen4.exe) fixed it for me.
I guess this missing symbol didn't matter in earlier versions but it looks like it does in 0.026.
Paul T.