patch 8.0.0647: syntax highlighting can make cause a freeze commit https://github.com/vim/vim/commit/06f1ed2f78c5c03af95054fc3a8665df39dec362 Author: Bram Moolenaar <Bram@vim.org> Date: Sun Jun 18 22:41:03 2017 +0200 patch 8.0.0647: syntax highlighting can make cause a freeze Problem: Syntax highlighting can make cause a freeze. Solution: Apply 'redrawtime' to syntax highlighting, per window.

--- a/src/normal.c
+++ b/src/normal.c
@@ -5477,6 +5477,14 @@ nv_clear(cmdarg_T *cap)
 #ifdef FEAT_SYN_HL
 	/* Clear all syntax states to force resyncing. */
 	syn_stack_free_all(curwin->w_s);
+# ifdef FEAT_RELTIME
+	{
+	    win_T *wp;
+
+	    FOR_ALL_WINDOWS(wp)
+		wp->w_s->b_syn_slow = FALSE;
+	}
+# endif
 #endif
 	redraw_later(CLEAR);
     }