Only update the system caret when we have the focus. This was

apparently causing the weird caret behaviour in Change Settings,
because that routine was still being called...

[originally from svn r1083]

window.c

@@ -1665,6 +1665,7 @@ static LRESULT CALLBACK WndProc (HWND hwnd, UINT message,
  * have one.)
  */
 void sys_cursor(int x, int y) {
+    if (has_focus)
 	SetCaretPos(x * font_width, y * font_height);
 }