diff --git a/applications/lazstats/LazStats.chm b/applications/lazstats/LazStats.chm
index 79df4c823..1c3c7a5ab 100644
Binary files a/applications/lazstats/LazStats.chm and b/applications/lazstats/LazStats.chm differ
diff --git a/applications/lazstats/docs/HelpNDoc/LazStats.hnd b/applications/lazstats/docs/HelpNDoc/LazStats.hnd
index d67b61614..029f689ac 100644
Binary files a/applications/lazstats/docs/HelpNDoc/LazStats.hnd and b/applications/lazstats/docs/HelpNDoc/LazStats.hnd differ
diff --git a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm
index 37170774f..79fefe996 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm
+++ b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.lfm
@@ -31,6 +31,8 @@ inherited XvsMultYForm: TXvsMultYForm
     inherited HelpBtn: TButton
       Left = 36
       Top = 459
+      HelpType = htKeyword
+      HelpKeyword = 'html/PlotXVersusMultipleYValues.htm'
     end
     inherited ButtonBevel: TBevel
       Top = 443
diff --git a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas
index c7ef9e486..265d5d27b 100644
--- a/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas
+++ b/applications/lazstats/source/forms/analysis/descriptive/xvsmultyunit.pas
@@ -47,6 +47,7 @@ type
     procedure AdjustConstraints; override;
     procedure Compute; override;
     procedure UpdateBtnStates; override;
+    function Validate(out AMsg: String; out AControl: TWinControl): Boolean; override;
 
   public
     constructor Create(AOwner: TComponent); override;
@@ -84,24 +85,7 @@ var
   ColLabels: StrDyneVec = nil;
   selected: IntDyneVec = nil;
 begin
-  if XEdit.Text = '' then
-  begin
-    ErrorMsg('No X variable selected.');
-    exit;
-  end;
-
-  if YBox.Items.Count = 0 then
-  begin
-    ErrorMsg('No Y variables selected.');
-    exit;
-  end;
-
   xCol := GetVariableIndex(OS3MainFrm.DataGrid, Trim(XEdit.Text));
-  if xCol = -1 then
-  begin
-    ErrorMsg('X variable not found.');
-    exit;
-  end;
 
   nY := YBox.Items.Count;
   NoSelected := nY + 1;   // one more for the x column, needed by Correlations()
@@ -220,6 +204,37 @@ begin
 end;
 
 
+function TXvsMultYForm.Validate(out AMsg: String; out AControl: TWinControl): Boolean;
+var
+  xCol: Integer;
+begin
+  Result := false;
+
+  if XEdit.Text = '' then
+  begin
+    AControl := XEdit;
+    AMsg := 'No X variable selected.';
+    exit;
+  end;
+
+  xCol := GetVariableIndex(OS3MainFrm.DataGrid, Trim(XEdit.Text));
+  if xCol = -1 then
+  begin
+    AControl := XEdit;
+    AMsg := 'X variable not found.';
+    exit;
+  end;
+
+  if YBox.Items.Count = 0 then
+  begin
+    AControl := VarList;
+    AMsg := 'No Y variables selected.';
+    exit;
+  end;
+
+  Result := true;
+end;
+
 procedure TXvsMultYForm.VarListDblClick(Sender: TObject);
 var
   index: integer;