Be more sophisticated about enabling synchronized updates when there is

an overlay and treat it like the active pane (use for commands which
move the cursor only). When there is an overlay also use it for all
panes and not just the active pane. GitHub issue 2826.

2 files changed, 29 insertions, 5 deletions

diff --git a/screen-write.c b/screen-write.c
index 01f8a097..c09d09ab 100644
--- a/screen-write.c
+++ b/screen-write.c
@@ -197,9 +197,20 @@ screen_write_initctx(struct screen_write_ctx *ctx, struct tty_ctx *ttyctx,
 		}
 	}
 
-	if (ctx->wp != NULL &&
-	    (~ctx->flags & SCREEN_WRITE_SYNC) &&
-	    (sync || ctx->wp != ctx->wp->window->active)) {
+	if (~ctx->flags & SCREEN_WRITE_SYNC) {
+		/*
+		 * For the active pane or for an overlay (no pane), we want to
+		 * only use synchronized updates if requested (commands that
+		 * move the cursor); for other panes, always use it, since the
+		 * cursor will have to move.
+		 */
+		if (ctx->wp != NULL) {
+			if (ctx->wp != ctx->wp->window->active)
+				ttyctx->num = 1;
+			else
+				ttyctx->num = sync;
+		} else
+			ttyctx->num = 0x10|sync;
 		tty_write(tty_cmd_syncstart, ttyctx);
 		ctx->flags |= SCREEN_WRITE_SYNC;
 	}
diff --git a/tty.c b/tty.c
index 2a9f8b01..f93f6c57 100644
--- a/tty.c
+++ b/tty.c
@@ -2039,9 +2039,22 @@ tty_cmd_rawstring(struct tty *tty, const struct tty_ctx *ctx)
 }
 
 void
-tty_cmd_syncstart(struct tty *tty, __unused const struct tty_ctx *ctx)
+tty_cmd_syncstart(struct tty *tty, const struct tty_ctx *ctx)
 {
-	tty_sync_start(tty);
+	if (ctx->num == 0x11) {
+		/*
+		 * This is an overlay and a command that moves, the cursor so
+		 * start synchronized updates.
+		 */
+		tty_sync_start(tty);
+	} else if (~ctx->num & 0x10) {
+		/*
+		 * This is a pane. If there is an overlay, always start;
+		 * otherwise, only if requested.
+		 */
+		if (ctx->num || tty->client->overlay_draw != NULL)
+			tty_sync_start(tty);
+	}
 }
 
 void