redisplay w/o minibuffer broken

Version: all known, including 21.4, 21.5. Frames without minibuffer are not displayed correctly on X device. The lowest line of non-minibuffer window in the frame gets overlapped with modeline as shown in an attached window dump. Redisplay related variables are as follows. (specifier-spec-list menubar-visible-p) ((global (nil))) (default-toolbar-position) top (specifier-spec-list default-toolbar-visible-p) ((global (nil))) (specifier-spec-list toolbar-buttons-captioned-p) ((global (nil . t)))