diff --git a/app/sheet.c b/app/sheet.c
index 5da27cc8..59fd9ac1 100644
--- a/app/sheet.c
+++ b/app/sheet.c
@@ -1,4 +1,6 @@
+#ifndef _GNU_SOURCE
 #define _GNU_SOURCE
+#endif
 #ifndef _XOPEN_SOURCE_EXTENDED
 #define _XOPEN_SOURCE_EXTENDED
 #endif
@@ -448,18 +450,9 @@ int ZSV_MAIN_FUNC(ZSV_COMMAND)(int argc, const char *argv[], struct zsv_opts *op
 const char *display_cell(struct zsv_sheet_buffer *buff, size_t data_row, size_t data_col, int row, int col) {
   char *str = (char *)zsv_sheet_buffer_cell_display(buff, data_row, data_col);
   size_t len = str ? strlen(str) : 0;
-  if (len == 0 || has_multibyte_char(str, len < ZTV_CELL_DISPLAY_WIDTH ? len : ZTV_CELL_DISPLAY_WIDTH) == 0) {
-    // temporarily add a NULL delimiter
-    int ch = str[ZTV_CELL_DISPLAY_WIDTH - 1];
-    str[ZTV_CELL_DISPLAY_WIDTH - 1] = '\0'; // ensure a blank space between cells
-    mvprintw(row, col * ZTV_CELL_DISPLAY_WIDTH, "%-*s", ZTV_CELL_DISPLAY_WIDTH, str);
-    str[ZTV_CELL_DISPLAY_WIDTH - 1] = ch;
-    /*
-    mvprintw(row, col * ZTV_CELL_DISPLAY_WIDTH, "%-*.*s", ZTV_CELL_DISPLAY_WIDTH,
-             len < ZTV_CELL_DISPLAY_WIDTH ? len : ZTV_CELL_DISPLAY_WIDTH - 1,
-             str);
-    */
-  } else {
+  if (len == 0 || has_multibyte_char(str, len < ZTV_CELL_DISPLAY_WIDTH ? len : ZTV_CELL_DISPLAY_WIDTH) == 0)
+    mvprintw(row, col * ZTV_CELL_DISPLAY_WIDTH, "%-*.*s", ZTV_CELL_DISPLAY_WIDTH, ZTV_CELL_DISPLAY_WIDTH - 1, str);
+  else {
     size_t used_width;
     int err = 0;
     unsigned char *s = (unsigned char *)str;
diff --git a/app/test/Makefile b/app/test/Makefile
index 6aaeb87f..931f4b3a 100644
--- a/app/test/Makefile
+++ b/app/test/Makefile
@@ -559,13 +559,12 @@ test-compare: test-%: ${BUILD_DIR}/bin/zsv_%${EXE}
 test-sheet: test-%: ${BUILD_DIR}/bin/zsv_%${EXE} worldcitiespop_mil.csv test-sheet-all
 
 test-sheet-all: test-sheet-1 test-sheet-2 test-sheet-3 test-sheet-4
-	@(! tmux kill-session -t $@ 2>/dev/null && ${TEST_PASS} || ${TEST_FAIL})
+	@(for SESSION in $^; do ! tmux kill-session -t "$$SESSION" 2>/dev/null; done && ${TEST_PASS} || ${TEST_FAIL})
 
 test-sheet-1: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 	@${TEST_INIT}
 	@echo 'set-option default-terminal "tmux-256color"' > ~/.tmux.conf
 	@(tmux new-session -x 1000 -y 5 -d -s $@ "${PREFIX} $< worldcitiespop_mil.csv" && \
-	tmux set-window-option -t test-sheet prefix none && \
 	sleep 0.5 && \
 	tmux capture-pane -t $@ -p ${REDIRECT1} ${TMP_DIR}/$@.out && \
 	tmux send-keys -t $@ "q" && \
@@ -574,7 +573,6 @@ test-sheet-1: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 test-sheet-2: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 	@${TEST_INIT}
 	@(tmux new-session -x 1000 -y 5 -d -s $@ "${PREFIX} $< worldcitiespop_mil.csv" && \
-	tmux set-window-option -t test-sheet prefix none && \
 	sleep 0.5 && \
 	tmux send-keys -t $@ "C-F" && \
 	tmux capture-pane -t $@ -p ${REDIRECT1} ${TMP_DIR}/$@.out && \
@@ -584,7 +582,6 @@ test-sheet-2: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 test-sheet-3: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 	@${TEST_INIT}
 	@(tmux new-session -x 1000 -y 5 -d -s $@ "${PREFIX} $< worldcitiespop_mil.csv" && \
-	tmux set-window-option -t test-sheet prefix none && \
 	sleep 0.5 && \
 	tmux send-keys -t $@ "f" "sarmaj" Enter && \
 	sleep 0.5 && \
@@ -595,7 +592,6 @@ test-sheet-3: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 test-sheet-4: ${BUILD_DIR}/bin/zsv_sheet${EXE}
 	@${TEST_INIT}
 	@(tmux new-session -x 1000 -y 5 -d -s $@ "${PREFIX} $< worldcitiespop_mil.csv" && \
-	tmux set-window-option -t test-sheet prefix none && \
 	sleep 0.5 && \
 	tmux send-keys -t $@ "C-F" "C-F" "C-B" && \
 	tmux capture-pane -t $@ -p ${REDIRECT1} ${TMP_DIR}/$@.out && \
diff --git a/app/test/expected/test-sheet4.out b/app/test/expected/test-sheet4.out
deleted file mode 100644
index 84ac8386..00000000
--- a/app/test/expected/test-sheet4.out
+++ /dev/null
@@ -1,5 +0,0 @@
-Row #     Country   City      AccentCit Region    Populatio Latitude  Longitude
-999995    ml        fallou    Fallou    08                  15.516666 -4.366666
-999996    gw        quenem    Quenem    04                  12.228333 -15.64444
-999997    ph        villa gar Villa Gar 29                  17.033333 120.45
-999997