small changes.

Author: RuedigerLunde

aima-core/src/main/java/aima/core/environment/vacuum/MazeVacuumEnvironment.java

@@ -32,7 +32,7 @@ public MazeVacuumEnvironment(int xDim, int yDim) {
 		this(xDim, yDim, 0.5, 0);
 	}
 
-	// Obstacles are marked by with locationState==null
+	// Obstacles are marked with locationState==null
 	public MazeVacuumEnvironment(int xDim, int yDim, double dirtProbability, double obstacleProbability) {
 		super(createLocations(xDim * yDim));
 		xDimension = xDim;

aima-gui/src/main/java/aima/gui/fx/views/SudokuViewCtrl.java

@@ -4,10 +4,7 @@
 import javafx.geometry.Pos;
 import javafx.geometry.VPos;
 import javafx.scene.control.ComboBox;
-import javafx.scene.layout.ColumnConstraints;
-import javafx.scene.layout.GridPane;
-import javafx.scene.layout.RowConstraints;
-import javafx.scene.layout.StackPane;
+import javafx.scene.layout.*;
 
 import java.util.ArrayList;
 import java.util.List;
@@ -65,10 +62,13 @@ public SudokuViewCtrl(StackPane viewRoot) {
     }
 
     public void clear(boolean allDigits) {
-        for (int i = 0; i < 81; i++) {
-            ComboBox<String> combo = combos.get(i);
-            if (allDigits || !isFixed(i % 9 + 1, i / 9 + 1))
-                combo.getSelectionModel().select(0);
+        for (int row = 1; row <= 9; row++) {
+            for (int col = 1; col <= 9; col++) {
+                if (allDigits || !isFixed(col, row)) {
+                    clearDigit(col, row);
+                    setGrey(col, row, false);
+                }
+            }
         }
     }
 
@@ -100,6 +100,10 @@ public boolean isFixed(int col, int row) {
         return selIdx >= 10;
     }
 
+    public void setGrey(int col, int row, boolean b) {
+        getCombo(col, row).setOpacity(b ? 0.5 : 1);
+    }
+
     private ComboBox<String> getCombo(int col, int row) {
         assert col >= 1 && col <= 9;
         assert row >= 1 && row <= 9;