comctl32: Add a check for setting number of parts in the statusbar to zero.

dlls/comctl32/status.c

@@ -665,6 +665,8 @@ STATUSBAR_SetParts (STATUS_INFO *infoPtr, INT count, LPINT parts)
 
     TRACE("(%d,%p)\n", count, parts);
 
+    if(!count) return FALSE;
+
     oldNumParts = infoPtr->numParts;
     infoPtr->numParts = count;
     if (oldNumParts > infoPtr->numParts) {

dlls/comctl32/tests/status.c

@@ -382,6 +382,12 @@ static void test_status_control(void)
     /* Reset number of parts */
     r = SendMessage(hWndStatus, SB_SETPARTS, 2, (LPARAM)nParts);
     expect(TRUE,r);
+    r = SendMessage(hWndStatus, SB_GETPARTS, 0, 0);
+    ok(r == 2, "Expected 2, got %d\n", r);
+    r = SendMessage(hWndStatus, SB_SETPARTS, 0, 0);
+    expect(FALSE,r);
+    r = SendMessage(hWndStatus, SB_GETPARTS, 0, 0);
+    ok(r == 2, "Expected 2, got %d\n", r);
 
     /* Set the minimum height and get rectangle information again */
     SendMessage(hWndStatus, SB_SETMINHEIGHT, 50, 0);