The refresh rate for the action needs to be high too.

config.def.h

@@ -15,7 +15,7 @@ static unsigned int tripleclicktimeout = 600;
 
 /* frames per second st should at maximum draw to the screen */
 static unsigned int xfps = 60;
-static unsigned int actionfps = 5;
+static unsigned int actionfps = 30;
 
 /* TERM value */
 static char termname[] = "st-256color";