fixed button dups

.idea/discord.xml

@@ -0,0 +1,7 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<project version="4">
+  <component name="DiscordProjectSettings">
+    <option name="show" value="PROJECT_FILES" />
+    <option name="description" value="" />
+  </component>
+</project>

src/DrawingBoard.java

@@ -131,6 +131,7 @@ public class DrawingBoard extends Panel implements DrawingEngine
 
     public void setShapeButtons(ArrayList<Button> buttons)
     {
+        ShapeButtons.removeAll();
         for (Button button : buttons)
         {
             ShapeButtons.add(button);