Fix - use drawopt also for graph drawing in TTree

For histogram option also stored as fOption and therefore not necessary

Author: linev

modules/draw/TTree.mjs

@@ -112,7 +112,7 @@ async function treeDrawProgress(obj, final) {
          if (final) console.log('no result after tree drawing');
          this.last_pr = false; // return false indicating no drawing is done
       } else {
-         this.last_pr = drawTreeDrawResult(this.drawid, obj).then(p => {
+         this.last_pr = drawTreeDrawResult(this.drawid, obj, this.drawopt).then(p => {
             this.obj_painter = p;
             if (!final) this.last_pr = null;
             return p; // return painter for histogram

modules/tree.mjs

@@ -875,9 +875,13 @@ class TDrawSelector extends TSelector {
 
       if (args.drawopt !== undefined)
          this.histo_drawopt = args.drawopt;
+      else if (this.graph)
+         this.histo_drawopt = 'P';
       else
          this.histo_drawopt = (this.ndim === 2) ? 'col' : '';
 
+      args.drawopt = this.histo_drawopt;
+
       return true;
    }