diff --git a/src/main/java/de/neemann/digital/gui/state/State.java b/src/main/java/de/neemann/digital/gui/state/State.java
index 5887cbac8..cff94d57d 100644
--- a/src/main/java/de/neemann/digital/gui/state/State.java
+++ b/src/main/java/de/neemann/digital/gui/state/State.java
@@ -8,6 +8,8 @@ import javax.swing.border.Border;
 import java.awt.event.ActionEvent;
 
 /**
+ * A simple state
+ *
  * @author hneemann
  */
 public class State implements StateInterface {
@@ -16,16 +18,26 @@ public class State implements StateInterface {
     private JComponent indicator;
     private StateManager stateManager;
 
+    /**
+     * Creates new state
+     */
     public State() {
     }
 
+    /**
+     * The JComponent used to indicate the state
+     *
+     * @param indicator the JComponent
+     * @param <C>       the type of the JComponent
+     * @return the JComponent for call chaining
+     */
     public <C extends JComponent> C setIndicator(C indicator) {
         this.indicator = indicator;
         indicator.setBorder(DISABLED_BORDER);
         return indicator;
     }
 
-    public void setStateManager(StateManager stateManager) {
+    void setStateManager(StateManager stateManager) {
         this.stateManager = stateManager;
     }
 
@@ -41,6 +53,13 @@ public class State implements StateInterface {
             indicator.setBorder(DISABLED_BORDER);
     }
 
+    /**
+     * Creates a tooltip action which activates the state
+     *
+     * @param name the name of the action to create
+     * @param icon the icon to use
+     * @return the acttion
+     */
     public ToolTipAction createToolTipAction(String name, Icon icon) {
         return new ToolTipAction(name, icon) {
             @Override
@@ -50,6 +69,9 @@ public class State implements StateInterface {
         };
     }
 
+    /**
+     * Activates this state
+     */
     public void activate() {
         stateManager.setState(this);
     }
diff --git a/src/main/java/de/neemann/digital/gui/state/StateInterface.java b/src/main/java/de/neemann/digital/gui/state/StateInterface.java
index 7b2cf4564..853f03b9d 100644
--- a/src/main/java/de/neemann/digital/gui/state/StateInterface.java
+++ b/src/main/java/de/neemann/digital/gui/state/StateInterface.java
@@ -1,11 +1,19 @@
 package de.neemann.digital.gui.state;
 
 /**
+ * A simple state
+ *
  * @author hneemann
  */
 public interface StateInterface {
+    /**
+     * Is called if the state is entered
+     */
     void enter();
 
+    /**
+     * Is called if the state is leaved
+     */
     void leave();
 
 }
diff --git a/src/main/java/de/neemann/digital/gui/state/StateManager.java b/src/main/java/de/neemann/digital/gui/state/StateManager.java
index 5e2fffef2..71f6d5afa 100644
--- a/src/main/java/de/neemann/digital/gui/state/StateManager.java
+++ b/src/main/java/de/neemann/digital/gui/state/StateManager.java
@@ -1,15 +1,25 @@
 package de.neemann.digital.gui.state;
 
 /**
+ * Organizes the state switches
+ *
  * @author hneemann
  */
 public class StateManager {
 
     private StateInterface actualState;
 
+    /**
+     * Creates a new instance
+     */
     public StateManager() {
     }
 
+    /**
+     * Activates the given state
+     *
+     * @param state the state to activate
+     */
     public void setState(StateInterface state) {
         if (actualState != null)
             actualState.leave();
@@ -18,6 +28,13 @@ public class StateManager {
             actualState.enter();
     }
 
+    /**
+     * Registers a state to this manager
+     *
+     * @param state the state to register
+     * @param <T>   the type of the state
+     * @return this for call chaining
+     */
     public <T extends State> T register(T state) {
         state.setStateManager(this);
         return state;
diff --git a/src/main/java/de/neemann/digital/gui/state/package-info.java b/src/main/java/de/neemann/digital/gui/state/package-info.java
new file mode 100644
index 000000000..62929ba6f
--- /dev/null
+++ b/src/main/java/de/neemann/digital/gui/state/package-info.java
@@ -0,0 +1,7 @@
+/**
+ * Used to handle the applications state.
+ * States a re running, microStepping, editing
+ *
+ * @author hneemann
+ */
+package de.neemann.digital.gui.state;