Shift+Tab arrives from every frontend as ISO_Left_Tab (0xfe20), which
has no Unicode value and lies outside the function keysym range, so
ipckeysym gave key 0 and the documented Shift-Tab wrap through search
results never reached the engine; GTK moved focus instead. KP_Enter and
KP_Tab likewise became unknown special keys, so the keypad Enter
committed the reading and passed a newline instead of taking the
highlighted candidate.
Hojun-Cho
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