diff --git a/Irony.GrammarExplorer/fmGrammarExplorer.Designer.cs b/Irony.GrammarExplorer/fmGrammarExplorer.Designer.cs
index 670f187..1027c3a 100644
--- a/Irony.GrammarExplorer/fmGrammarExplorer.Designer.cs
+++ b/Irony.GrammarExplorer/fmGrammarExplorer.Designer.cs
@@ -49,7 +49,7 @@ private void InitializeComponent() {
       this.btnRun = new System.Windows.Forms.Button();
       this.btnFileOpen = new System.Windows.Forms.Button();
       this.btnParse = new System.Windows.Forms.Button();
-      this.splitter3 = new System.Windows.Forms.Splitter();
+      this.splitRight = new System.Windows.Forms.Splitter();
       this.tabOutput = new System.Windows.Forms.TabControl();
       this.pageSyntaxTree = new System.Windows.Forms.TabPage();
       this.tvParseTree = new System.Windows.Forms.TreeView();
@@ -122,7 +122,7 @@ private void InitializeComponent() {
       this.chkExcludeComments = new System.Windows.Forms.CheckBox();
       this.lblTraceComment = new System.Windows.Forms.Label();
       this.pageOutput = new System.Windows.Forms.TabPage();
-      this.txtOutput = new WinForms.ConsoleTextBox();
+      this.txtOutput = new Irony.WinForms.ConsoleTextBox();
       this.pnlRuntimeInfo = new System.Windows.Forms.Panel();
       this.label14 = new System.Windows.Forms.Label();
       this.lblGCCount = new System.Windows.Forms.Label();
@@ -250,7 +250,7 @@ private void InitializeComponent() {
       //
       this.pageTest.Controls.Add(this.txtSource);
       this.pageTest.Controls.Add(this.panel1);
-      this.pageTest.Controls.Add(this.splitter3);
+      this.pageTest.Controls.Add(this.splitRight);
       this.pageTest.Controls.Add(this.tabOutput);
       this.pageTest.Location = new System.Drawing.Point(4, 22);
       this.pageTest.Name = "pageTest";
@@ -343,14 +343,14 @@ private void InitializeComponent() {
       this.btnParse.UseVisualStyleBackColor = true;
       this.btnParse.Click += new System.EventHandler(this.btnParse_Click);
       //
-      // splitter3
+      // splitRight
       //
-      this.splitter3.Dock = System.Windows.Forms.DockStyle.Right;
-      this.splitter3.Location = new System.Drawing.Point(655, 3);
-      this.splitter3.Name = "splitter3";
-      this.splitter3.Size = new System.Drawing.Size(6, 349);
-      this.splitter3.TabIndex = 14;
-      this.splitter3.TabStop = false;
+      this.splitRight.Dock = System.Windows.Forms.DockStyle.Right;
+      this.splitRight.Location = new System.Drawing.Point(655, 3);
+      this.splitRight.Name = "splitRight";
+      this.splitRight.Size = new System.Drawing.Size(6, 349);
+      this.splitRight.TabIndex = 14;
+      this.splitRight.TabStop = false;
       //
       // tabOutput
       //
@@ -1283,7 +1283,6 @@ private void InitializeComponent() {
       this.pnlParserTraceTop.ResumeLayout(false);
       this.pnlParserTraceTop.PerformLayout();
       this.pageOutput.ResumeLayout(false);
-      this.pageOutput.PerformLayout();
       this.pnlRuntimeInfo.ResumeLayout(false);
       this.pnlRuntimeInfo.PerformLayout();
       this.ResumeLayout(false);
@@ -1301,7 +1300,7 @@ private void InitializeComponent() {
     private System.Windows.Forms.ComboBox cboGrammars;
     private System.Windows.Forms.Label label2;
     private System.Windows.Forms.TabPage pageTest;
-    private System.Windows.Forms.Splitter splitter3;
+    private System.Windows.Forms.Splitter splitRight;
     private System.Windows.Forms.TabControl tabOutput;
     private System.Windows.Forms.TabPage pageAst;
     private System.Windows.Forms.TabPage pageSyntaxTree;
diff --git a/Irony.GrammarExplorer/fmGrammarExplorer.cs b/Irony.GrammarExplorer/fmGrammarExplorer.cs
index 21df429..ee604b6 100644
--- a/Irony.GrammarExplorer/fmGrammarExplorer.cs
+++ b/Irony.GrammarExplorer/fmGrammarExplorer.cs
@@ -53,6 +53,8 @@ private void fmExploreGrammar_Load(object sender, EventArgs e) {
         chkDisableHili.Checked = Settings.Default.DisableHili;
         chkAutoRefresh.Checked = Settings.Default.AutoRefresh;
         cboGrammars.SelectedIndex = Settings.Default.LanguageIndex; //this will build parser and start colorizer
+        if (Application.RenderWithVisualStyles)
+          splitRight.BackColor = SystemColors.ControlLightLight;
       } catch { }
       _loaded = true;
     }
@@ -361,6 +363,9 @@ private void RunSample() {
           ParseSample();
         if (_parseTree.ParserMessages.Count > 0) return;
 
+        //show output console
+        tabBottom.SelectedTab = pageOutput;
+        btnRun.Enabled = false;
         GC.Collect(); //to avoid disruption of perf times with occasional collections
         oldGcCount = GC.CollectionCount(0);
         System.Threading.Thread.Sleep(100);
@@ -374,11 +379,11 @@ private void RunSample() {
         var gcCount = GC.CollectionCount(0) - oldGcCount;
         lblGCCount.Text = gcCount.ToString();
         WriteOutput(output);
-        tabBottom.SelectedTab = pageOutput;
       } catch (ScriptException ex) {
         ShowRuntimeError(ex);
       } finally {
         sw.Stop();
+        btnRun.Enabled = true;
       }//finally
     }//method
 
diff --git a/Languages/Refal/Runtime/RefalLibrary.cs b/Languages/Refal/Runtime/RefalLibrary.cs
index 2ec9894..a37bf2c 100644
--- a/Languages/Refal/Runtime/RefalLibrary.cs
+++ b/Languages/Refal/Runtime/RefalLibrary.cs
@@ -10,6 +10,7 @@
 using Irony.Interpreter.Ast;
 using Irony.Interpreter;
 using System.Numerics;
+using System.Collections.Concurrent;
 
 namespace Refal.Runtime
 {
@@ -43,9 +44,9 @@ public class RefalLibrary
 		public RefalLibrary(ScriptThread thread)
 		{
 			ScriptThread = thread;
-			OpenFiles = new Dictionary<string, object>();
-			BuriedKeys = new Dictionary<string, PassiveExpression>();
-			BuriedValues = new Dictionary<string, PassiveExpression>();
+			OpenFiles = new ConcurrentDictionary<string, object>();
+			BuriedKeys = new ConcurrentDictionary<string, PassiveExpression>();
+			BuriedValues = new ConcurrentDictionary<string, PassiveExpression>();
 			CommandLineArguments = null;
 		}