diff --git a/Client/Tools/UfrmBoundaries.pas b/Client/Tools/UfrmBoundaries.pas
index 65a7cb0..6d7a51f 100644
--- a/Client/Tools/UfrmBoundaries.pas
+++ b/Client/Tools/UfrmBoundaries.pas
@@ -92,11 +92,13 @@ end;
 procedure TfrmBoundaries.tbMaxZChange(Sender: TObject);
 begin
   seMaxZ.Value := tbMaxZ.Position;
+  frmMain.InvalidateFilter;
 end;
 
 procedure TfrmBoundaries.tbMinZChange(Sender: TObject);
 begin
   seMinZ.Value := tbMinZ.Position;
+  frmMain.InvalidateFilter;
 end;
 
 procedure TfrmBoundaries.MouseLeave(var msg: TLMessage);
diff --git a/Client/Tools/UfrmFilter.lfm b/Client/Tools/UfrmFilter.lfm
index 3caf6b1..183af28 100644
--- a/Client/Tools/UfrmFilter.lfm
+++ b/Client/Tools/UfrmFilter.lfm
@@ -39,6 +39,7 @@ object frmFilter: TfrmFilter
       'Exclusive'
       'Inclusive'
     )
+    OnClick = rgFilterTypeClick
     TabOrder = 0
   end
   object GroupBox1: TGroupBox
@@ -230,6 +231,7 @@ object frmFilter: TfrmFilter
       Width = 85
       BorderSpacing.Around = 4
       Caption = 'Filter active'
+      OnChange = cbTileFilterChange
       TabOrder = 1
     end
   end
@@ -252,6 +254,7 @@ object frmFilter: TfrmFilter
       Align = alTop
       BorderSpacing.Around = 4
       Caption = 'Filter active'
+      OnChange = cbHueFilterChange
       TabOrder = 0
     end
     object vdtHues: TVirtualDrawTree
diff --git a/Client/Tools/UfrmFilter.pas b/Client/Tools/UfrmFilter.pas
index f062056..06b249d 100644
--- a/Client/Tools/UfrmFilter.pas
+++ b/Client/Tools/UfrmFilter.pas
@@ -59,11 +59,14 @@ type
     vdtHues: TVirtualDrawTree;
     procedure btnClearClick(Sender: TObject);
     procedure btnDeleteClick(Sender: TObject);
+    procedure cbHueFilterChange(Sender: TObject);
+    procedure cbTileFilterChange(Sender: TObject);
     procedure FormCreate(Sender: TObject);
     procedure FormDestroy(Sender: TObject);
     procedure FormShow(Sender: TObject);
     procedure mnuUncheckHuesClick(Sender: TObject);
     procedure mnuCheckHuesClick(Sender: TObject);
+    procedure rgFilterTypeClick(Sender: TObject);
     procedure vdtFilterDragDrop(Sender: TBaseVirtualTree; Source: TObject;
       DataObject: IDataObject; Formats: TFormatArray; Shift: TShiftState;
       Pt: TPoint; var Effect: Integer; Mode: TDropMode);
@@ -137,6 +140,11 @@ begin
   end;
 end;
 
+procedure TfrmFilter.rgFilterTypeClick(Sender: TObject);
+begin
+  frmMain.InvalidateFilter;
+end;
+
 procedure TfrmFilter.vdtFilterDragDrop(Sender: TBaseVirtualTree;
   Source: TObject; DataObject: IDataObject; Formats: TFormatArray;
   Shift: TShiftState; Pt: TPoint; var Effect: Integer; Mode: TDropMode);
@@ -160,6 +168,7 @@ begin
         targetTileInfo := Sender.GetNodeData(node);
         targetTileInfo^.ID := sourceTileInfo^.ID;
         cbTileFilter.Checked := True;
+        frmMain.InvalidateFilter;
       end;
       selected := sourceTree.GetNextSelected(selected);
     end;
@@ -191,6 +200,7 @@ begin
   hueInfo := Sender.GetNodeData(Node);
   FCheckedHues.Bits[hueInfo^.ID] := (Sender.CheckState[node] = csCheckedNormal);
   cbHueFilter.Checked := True;
+  frmMain.InvalidateFilter;
 end;
 
 procedure TfrmFilter.vdtHuesDrawNode(Sender: TBaseVirtualTree;
@@ -321,6 +331,16 @@ begin
   vdtFilter.DeleteSelectedNodes;
 end;
 
+procedure TfrmFilter.cbHueFilterChange(Sender: TObject);
+begin
+  frmMain.InvalidateFilter;
+end;
+
+procedure TfrmFilter.cbTileFilterChange(Sender: TObject);
+begin
+  frmMain.InvalidateFilter;
+end;
+
 procedure TfrmFilter.btnClearClick(Sender: TObject);
 begin
   vdtFilter.Clear;
diff --git a/Client/UfrmMain.pas b/Client/UfrmMain.pas
index 418a9f3..333f7a9 100644
--- a/Client/UfrmMain.pas
+++ b/Client/UfrmMain.pas
@@ -42,6 +42,8 @@ type
   TVirtualTileArray = array of TVirtualTile;
 
   TAccessChangedListener = procedure(AAccessLevel: TAccessLevel) of object;
+  TScreenBufferState = (sbsValid, sbsIndexed, sbsFiltered);
+  TScreenBufferStates = set of TScreenBufferState;
 
   { TfrmMain }
 
@@ -276,8 +278,7 @@ type
     FLandscape: TLandscape;
     FTextureManager: TLandTextureManager;
     FScreenBuffer: TScreenBuffer;
-    FScreenBufferValid: Boolean;
-    FScreenBufferIndexed: Boolean;
+    FScreenBufferState: TScreenBufferStates;
     FCurrentTile: TWorldItem;
     FSelectedTile: TWorldItem;
     FGhostTile: TWorldItem;
@@ -312,6 +313,7 @@ type
     procedure SetY(const AValue: Integer);
     procedure UpdateCurrentTile;
     procedure UpdateCurrentTile(AX, AY: Integer);
+    procedure UpdateFilter;
     procedure UpdateSelection;
     procedure WriteChatMessage(ASender, AMessage: string);
     { Events }
@@ -332,6 +334,7 @@ type
     property CurrentTile: TWorldItem read FCurrentTile write SetCurrentTile;
     property SelectedTile: TWorldItem read FSelectedTile write SetSelectedTile;
     { Methods }
+    procedure InvalidateFilter;
     procedure RegisterAccessChangedListener(AListener: TAccessChangedListener);
     procedure SetPos(AX, AY: Word);
     procedure UnregisterAccessChangedListener(AListener: TAccessChangedListener);
@@ -738,7 +741,7 @@ begin
 
   FTextureManager := TLandTextureManager.Create;
   FScreenBuffer := TScreenBuffer.Create;
-  FScreenBufferValid := False;
+  FScreenBufferState := [];
   X := 0;
   Y := 0;
   edX.MaxValue := FLandscape.CellWidth;
@@ -854,6 +857,7 @@ begin
     oglGameWindow.Repaint;
     FLastDraw := Now;
   end;
+  Sleep(1);
   Done := False;
 end;
 
@@ -932,6 +936,7 @@ begin
     frmFilter.Locked := False;
   end else
     frmFilter.Hide;
+  InvalidateFilter;
 end;
 
 procedure TfrmMain.acFlatExecute(Sender: TObject);
@@ -1675,9 +1680,14 @@ begin
   glLoadIdentity;
 end;
 
+procedure TfrmMain.InvalidateFilter;
+begin
+  Exclude(FScreenBufferState, sbsFiltered);
+end;
+
 procedure TfrmMain.InvalidateScreenBuffer;
 begin
-  FScreenBufferValid := False;
+  Exclude(FScreenBufferState, sbsValid);
 end;
 
 procedure TfrmMain.PrepareScreenBlock(ABlockInfo: PBlockInfo);
@@ -1791,14 +1801,17 @@ var
 begin
   tileRect := GetSelectedRect;
 
-  if not FScreenBufferValid then
+  if not (sbsValid in FScreenBufferState) then
     RebuildScreenBuffer;
 
-  if not FScreenBufferIndexed then
+  if not (sbsIndexed in FScreenBufferState) then
   begin
     FScreenBuffer.UpdateShortcuts;
-    FScreenBufferIndexed := True;
+    Include(FScreenBufferState, sbsIndexed);
   end;
+
+  if not (sbsFiltered in FScreenBufferState) then
+    UpdateFilter;
   
   {if acFilter.Checked then
     staticsFilter := @frmFilter.Filter
@@ -2060,7 +2073,7 @@ var
   cell: TMapCell;
 begin
   PrepareScreenBlock(FScreenBuffer.UpdateSortOrder(AMapCell));
-  FScreenBufferIndexed := False;
+  Exclude(FScreenBufferState, sbsIndexed);
 
   //Find surrounding cells
   current := nil;
@@ -2102,7 +2115,7 @@ procedure TfrmMain.OnStaticElevated(AStaticItem: TStaticItem);
 begin
   AStaticItem.PrioritySolver := FScreenBuffer.GetSerial;
   PrepareScreenBlock(FScreenBuffer.UpdateSortOrder(AStaticItem));
-  FScreenBufferIndexed := False;
+  Exclude(FScreenBufferState, sbsIndexed);
 end;
 
 procedure TfrmMain.OnStaticHued(AStaticItem: TStaticItem);
@@ -2277,8 +2290,7 @@ begin
     PrepareScreenBlock(blockInfo);
 
   FScreenBuffer.UpdateShortcuts;
-  FScreenBufferValid := True;
-  FScreenBufferIndexed := True;
+  FScreenBufferState := [sbsValid, sbsIndexed];
 end;
 
 procedure TfrmMain.UpdateCurrentTile;
@@ -2327,6 +2339,31 @@ begin
   end;
 end;
 
+procedure TfrmMain.UpdateFilter;
+var
+  blockInfo: PBlockInfo;
+begin
+  blockInfo := nil;
+  while FScreenBuffer.Iterate(blockInfo) do
+  begin
+    if blockInfo^.State in [ssNormal, ssFiltered] then
+    begin
+      blockInfo^.State := ssNormal;
+      if (blockInfo^.Item.Z < frmBoundaries.tbMinZ.Position) or
+        (blockInfo^.Item.Z > frmBoundaries.tbMaxZ.Position) then
+      begin
+        blockInfo^.State := ssFiltered;
+      end else
+      if tbFilter.Down and (blockInfo^.Item is TStaticItem) and
+        (not frmFilter.Filter(TStaticItem(blockInfo^.Item))) then
+      begin
+        blockInfo^.State := ssFiltered;
+      end;
+    end;
+  end;
+  Include(FScreenBufferState, sbsFiltered);
+end;
+
 procedure TfrmMain.UpdateSelection;
 var
   selectedRect: TRect;