Don’t allow negative values for Size and Border width

Author: rafbm

public/js/lib/views/arrow_configuration_view.js

@@ -97,9 +97,12 @@ if (!('CSSArrowPlease' in window)) window.CSSArrowPlease = {};
       var target    = $(ev.currentTarget),
           val       = parseInt(target.val()),
           increment = ev.keyCode == 38 ? 1 : -1,
-          multiply  = ev.shiftKey ? 10 : 1;
+          multiply  = ev.shiftKey ? 10 : 1
+          newVal    = val + increment * multiply;
 
-      target.val(val + increment * multiply);
+      if (newVal < 0) newVal = 0;
+
+      target.val(newVal);
       this._updateModel(ev);
     }