diff --git a/src/gui/model/tangible.cpp b/src/gui/model/tangible.cpp
index 47dc6832c..8f3290960 100644
--- a/src/gui/model/tangible.cpp
+++ b/src/gui/model/tangible.cpp
@@ -93,5 +93,40 @@ namespace model {
   }
   
   
+  /**
+   * Expand this element and remember the expanded state.
+   * This is a generic Slot to connect UI signals against.
+   */
+  void
+  Tangible::slotExpand()
+  {
+    this->doExpand(true);
+    uiBus_.note (GenNode("expand", true));
+  }
+  
+  
+  /**
+   * Collapse or minimise this element and remember the collapsed state.
+   * This is a generic Slot to connect UI signals against.
+   */
+  void
+  Tangible::slotCollapse()
+  {
+    this->doExpand(false);
+    uiBus_.note (GenNode("expand", false));
+  }
+  
+  
+  /**
+   * @todo not clear yet what needs to be done
+   */
+  void
+  Tangible::slotReveal(ID child)
+  {
+    this->doReveal(child);
+    this->doRevealYourself();
+  }
+  
+  
   
 }} // namespace gui::model
diff --git a/src/gui/model/tangible.hpp b/src/gui/model/tangible.hpp
index 24935783d..8509043be 100644
--- a/src/gui/model/tangible.hpp
+++ b/src/gui/model/tangible.hpp
@@ -92,8 +92,10 @@ namespace model {
       void prepareCommand (Cmd const& prototype, Rec&& arguments);
       void issueCommand (Cmd const& preparedAction);
       
-      void slotExpand()               { this->doExpand(); }
-      void slotReveal()               { this->doReveal(); }
+      void slotExpand();
+      void slotCollapse();
+      
+      void slotReveal(ID child);
       
       void markMsg (string m)         { this->doMsg(m); }
       void markErr (string e)         { this->doErr(e); }
@@ -102,8 +104,9 @@ namespace model {
       
     protected:
       virtual void doReset()  =0;
-      virtual void doExpand() =0;
-      virtual void doReveal() =0;
+      virtual void doExpand (bool yes) =0;
+      virtual void doReveal (ID child) =0;
+      virtual void doRevealYourself () =0;
       
       virtual void doMsg (string)          =0;
       virtual void doErr (string)          =0;
diff --git a/tests/gui/test/mock-elm.hpp b/tests/gui/test/mock-elm.hpp
index 65b863c9c..c2a941430 100644
--- a/tests/gui/test/mock-elm.hpp
+++ b/tests/gui/test/mock-elm.hpp
@@ -88,43 +88,61 @@ namespace test{
       EventLog log_{this};
       
       bool virgin_{true};
+      bool expanded_{false};
       
       
       /* ==== Tangible interface ==== */
       
-      virtual void doReset()  override
+      virtual void
+      doReset()  override
         {
           log_.call(this->identify(), "reset");
+          expanded_ = false;
           virgin_ = true;
           log_.event("reset");
         }
       
-      virtual void doExpand()  override
+      virtual void
+      doExpand (bool yes)  override
         {
-          UNIMPLEMENTED ("mock doExpand");
+          log_.call(this->identify(), "expand", yes);
+          virgin_ = false;
+          expanded_ = yes;
+          log_.event(expanded_? "expanded" : "collapsed");
         }
       
-      virtual void doReveal()  override
+      virtual void
+      doReveal (ID child)  override
         {
           UNIMPLEMENTED ("mock doReveal");
         }
       
-      virtual void doMsg (string text)  override
+      virtual void
+      doRevealYourself()  override
+        {
+          UNIMPLEMENTED ("mock doRevealYourself");
+        }
+      
+      virtual void
+      doMsg (string text)  override
         {
           UNIMPLEMENTED ("mock doMsg");
         }
       
-      virtual void doErr (string text)  override
+      virtual void
+      doErr (string text)  override
         {
           UNIMPLEMENTED ("mock doErr");
         }
       
-      virtual void doFlash()  override
+      virtual void
+      doFlash()  override
         {
           UNIMPLEMENTED ("mock doFlash");
         }
       
-      virtual void doMark (GenNode const& mark)  override
+      virtual void
+      doMark (GenNode const& mark)  override
         {
           UNIMPLEMENTED ("mock doMark");
         }
@@ -172,13 +190,13 @@ namespace test{
       bool
       isTouched()  const
         {
-          UNIMPLEMENTED ("pristine status");
+          return not virgin_;
         }
       
       bool
       isExpanded()  const
         {
-          UNIMPLEMENTED ("UI element expansion status");
+          return expanded_;
         }