This concerns the characters that are left- and right-pointing thin arrows in the IBM set, numbers 26 and 27. If one of these characters is inserted in a document which is then saved and reloaded (I used the default file format), strange effects occur. With the right arrow (#26), the character is deleted and every character after it is shifted left to fill the gap; the shift is wrapped down through the whole document. With the left arrow (#27), usually nothing happens, but sometimes a few extra characters like “[1AC” are inserted (I haven’t been able to duplicate this reliably). Both effects make it impossible to create documents that use these characters.