Shitty attempt to debug

src/config.h

@@ -5,7 +5,7 @@ static const unsigned int borderpx	= 4;		/* border pixel of windows */
 static const unsigned int snap		= 16;		/* snap pixel (32)*/
 static const unsigned int gappx		= 0;
 static const unsigned int gappx2	= 40;
-static const unsigned int gapmodes[] = { 0, 40 };
+static const unsigned int gapmodes[] = { 0, 40, 80 };
 static const int showbar			= 1;		/* 0 means no bar */
 static const int topbar				= 0;		/* 0 means bottom bar */
 static const int usealtbar			= 1;		/* 1 means use non-dwm status bar */

src/dwm.c

@@ -1856,9 +1856,11 @@ togglegaps(const Arg *arg)
 void
 switchgaps(const Arg *arg) 
 {
-	selmon->gapidx = (selmon->gapidx + arg->i) % modeslen;
+	selmon->gapidx += arg->i; 
+	selmon->gapidx %= modeslen;
 
 	selmon->gappx = gapmodes[selmon->gapidx];
+	printf("####### GAPPX=%d GAPIDX=%d\n", selmon->gappx, selmon->gapidx);
 	arrange(selmon);
 }