[c-smile]

Consider <textarea> that has resizing handle on the corner (try to reply to this message to see it alive). And now try to imagine how would you render those diagonal lines in HTML/CSS ?

While in Sciter, that has such immediate mode rendering form the very beginning, you can simply draw them as:

   resizableElement.paintForeground = function(gfx) { // draw on top of background & content

      let box = this.getBoundingClientRect();
      gfx.moveTo(...); gfx.lineTo(...);
      gfx.moveTo(...); gfx.lineTo(...);
      ...
   }

Easy, right? And does not need to modify DOM and place artificial positioned elements.