csi: check for private marker in 'S' case

The handler for 'S' final character does not check for a private
marker. This can cause a conflict with a sequence called 'XTSMGRAPHICS'
which also has an 'S' final character, but uses the private marker '?'.
Without checking for a private marker, st will perform a scroll up
operation when XTSMGRAPHICS is seen, which can cause unexpected display
artifacts.

1 files changed, 1 insertions, 0 deletions

diff --git a/st.c b/st.c
index d6478f5..034954d 100644
--- a/st.c
+++ b/st.c
@@ -1728,6 +1728,7 @@ csihandle(void)
                 }
                 break;
         case 'S': /* SU -- Scroll <n> line up */
+                if (csiescseq.priv) break;
                 DEFAULT(csiescseq.arg[0], 1);
                 tscrollup(term.top, csiescseq.arg[0]);
                 break;