diff --git a/source/tabletools.lfm b/source/tabletools.lfm
index e45b86cf..bb881ebd 100644
--- a/source/tabletools.lfm
+++ b/source/tabletools.lfm
@@ -80,8 +80,8 @@ object frmTableTools: TfrmTableTools
       TabOrder = 0
       object ResultGrid: TLazVirtualStringTree
         Left = 0
-        Height = 189
-        Top = 241
+        Height = 192
+        Top = 238
         Width = 707
         Align = alClient
         Header.AutoSizeIndex = -1
@@ -105,18 +105,19 @@ object frmTableTools: TfrmTableTools
       end
       object tabsTools: TPageControl
         Left = 0
-        Height = 241
+        Height = 238
         Top = 0
         Width = 707
         ActivePage = tabMaintenance
         Align = alTop
+        AutoSize = True
         Images = MainForm.ImageListIcons8
         TabIndex = 0
         TabOrder = 1
         OnChange = ValidateControls
         object tabMaintenance: TTabSheet
           Caption = 'Maintenance'
-          ClientHeight = 208
+          ClientHeight = 205
           ClientWidth = 699
           ImageIndex = 39
           object lblOperation: TLabel
@@ -274,7 +275,7 @@ object frmTableTools: TfrmTableTools
         end
         object tabFind: TTabSheet
           Caption = 'Find text'
-          ClientHeight = 208
+          ClientHeight = 205
           ClientWidth = 699
           ImageIndex = 30
           object lblFindText: TLabel
@@ -492,7 +493,7 @@ object frmTableTools: TfrmTableTools
         end
         object tabSQLexport: TTabSheet
           Caption = 'SQL export'
-          ClientHeight = 208
+          ClientHeight = 205
           ClientWidth = 699
           ImageIndex = 9
           object lblExportData: TLabel
@@ -727,7 +728,7 @@ object frmTableTools: TfrmTableTools
         end
         object tabBulkTableEdit: TTabSheet
           Caption = 'Bulk table editor'
-          ClientHeight = 208
+          ClientHeight = 205
           ClientWidth = 699
           ImageIndex = 19
           object chkBulkTableEditDatabase: TCheckBox
@@ -871,7 +872,7 @@ object frmTableTools: TfrmTableTools
         end
         object tabGenerateData: TTabSheet
           Caption = 'Generate data'
-          ClientHeight = 208
+          ClientHeight = 205
           ClientWidth = 699
           ImageIndex = 130
           object lblGenerateDataNumRows: TLabel
diff --git a/source/tabletools.pas b/source/tabletools.pas
index 301b13c6..d1d8be97 100644
--- a/source/tabletools.pas
+++ b/source/tabletools.pas
@@ -2227,6 +2227,7 @@ var
   EnumValues: TStringList;
   TextVal: String;
   BinVal: String;
+  NumRows, NullsAmount: Int64;
 begin
   // Generate rows
   if not (DBObj.NodeType in [lntTable, lntView]) then begin
@@ -2258,7 +2259,10 @@ begin
 
   Randomize;
 
-  for i:=1 to StrToInt64Def(editGenerateDataNumRows.Text, 0) do begin
+  NumRows := StrToInt64Def(editGenerateDataNumRows.Text, 0);
+  NullsAmount := StrToInt64Def(editGenerateDataNullAmount.Text, 0);
+
+  for i:=1 to NumRows do begin
     Values.Clear;
     // Generate random values. Include some NULLs for columns which allow that.
     for Col in Columns do begin
@@ -2267,8 +2271,8 @@ begin
 
       // https://www.delphipraxis.net/31059-warscheinlichkeit-random.html
       if Col.AllowNull
-        and (StrToInt64Def(editGenerateDataNullAmount.Text, 0) > 0) // prevent division by zero
-        and (Random < (StrToInt64Def(editGenerateDataNullAmount.Text, 0) / 100))
+        and (NullsAmount > 0) // prevent division by zero
+        and (Random < (NullsAmount / 100))
         then begin
         Values.Add('NULL');
         Continue;