diff --git a/ImNodeSoup.cpp b/ImNodeSoup.cpp
index 2bf851e..14d1f7a 100644
--- a/ImNodeSoup.cpp
+++ b/ImNodeSoup.cpp
@@ -592,12 +592,13 @@ nodesoup::adj_list_t read_from_dot(const char* aDotData)
 
 
 
-
+constexpr std::size_t kInvadidVertex=static_cast<std::size_t>(-1);
+constexpr float kMinUIDist=9.0f;  // TODO: Calculate this with DPI?
 const float kWindowInitWidth = 800.0f;
 const float kWindowInitHeight= 600.0f;
 static ImVec2 gDisp{0.0f,0.0f};
 static float  gScale=1.0f;
-
+static nodesoup::vertex_id_t gSelectedVertex=kInvadidVertex;
 
 
 
@@ -649,68 +650,76 @@ static nodesoup::vertex_id_t GetPosAt(const ImVec2& aPos,const std::vector<NsPos
 
 
 
+
+
+
 static MoveRes MovePos(const std::vector<NsPosition>& aPositions)
 {
   MoveRes res;
 
   ImGuiIO& io = ImGui::GetIO();
 
-  if(!io.MouseDown[1] && !io.MouseReleased[1])
-    {
-      res.m_Moved=false;
-      res.m_Recalculate=false;
-
-      return res;
-    }
-
-  ImVec2 mouse_pos=io.MousePos;
-  nodesoup::vertex_id_t v_id=GetPosAt(mouse_pos,aPositions);
-  if(v_id==-1) // Not over a node
+  if(gSelectedVertex==kInvadidVertex) // No hay ninguno seleccionado
     {
-      res.m_Moved=false;
-      res.m_Recalculate=false;
-      return res;
-    }
+      if(io.MouseDown[1])
+        {
+          ImVec2 mouse_pos=io.MousePos;
+          gSelectedVertex=GetPosAt(mouse_pos,aPositions);
 
-  if(io.MouseDown[1])
-    {
-      res.m_Index=v_id;
-      res.m_Disp=io.MouseDelta/gScale;
-      res.m_Moved=true;
-      res.m_Recalculate=false;
-      return res;
-    }
 
-  if(io.MouseReleased[1])
-    {
-      res.m_Index=v_id;
-      res.m_Recalculate=true;
+          res.m_Index=gSelectedVertex;
+          res.m_Disp={0.0f,0.0f};
+          res.m_Moved=(gSelectedVertex==kInvadidVertex?false:true);
+          res.m_Recalculate=false;
 
-      if(io.MouseDragMaxDistanceSqr[1]<10)
-        {
-          res.m_Disp={kInvalidPos,kInvalidPos};
+          return res;
         }
       else
         {
-          res.m_Disp=io.MouseDelta/gScale;
-        }
+          res.m_Moved=false;
+          res.m_Recalculate=false;
 
-      return res;
+          return res;
+        }
     }
+  else // Hay un vertice seleccionado
+    {
+      if(io.MouseDown[1]) // Lo esta moviendo
+        {
+          res.m_Index=gSelectedVertex;
+          res.m_Disp=io.MouseDelta/gScale;
+          res.m_Moved=true;
+          res.m_Recalculate=false;
+          return res;
+        }
+      else // Ha dejado de pulsar
+        {
+          res.m_Index=gSelectedVertex;
+          res.m_Moved=true;
+          res.m_Recalculate=true;
 
-  assert(0);
-
-  res.m_Moved=false;
-  res.m_Recalculate=false;
+          if(io.MouseDragMaxDistanceSqr[1]<kMinUIDist)
+            {
+              res.m_Disp={kInvalidPos,kInvalidPos};
+            }
+          else
+            {
+              res.m_Disp=io.MouseDelta/gScale;
+            }
 
-  return res;
+          gSelectedVertex=kInvadidVertex;
 
+          return res;
+        }
+    }
 
+  assert(0);
 }
 
 
 
 
+
 static void DrawData(const nodesoup::adj_list_t& aAdjList,const std::vector<NsPosition>& aPositions,bool aAllowMove
                     ,bool aDrawDebug)
 {
diff --git a/fruchterman_reingold.cpp b/fruchterman_reingold.cpp
index 0ee7929..7e8a0df 100644
--- a/fruchterman_reingold.cpp
+++ b/fruchterman_reingold.cpp
@@ -183,10 +183,7 @@ void FruchtermanReingold::MovePos(vertex_id_t aVertexId,const ImVec2& aDisp,bool
     {
       if(aDisp.x==kInvalidPos && aDisp.y==kInvalidPos)
         {
-          if(m_Positions[aVertexId].m_Fixed)
-            {
-              m_Positions[aVertexId].m_Fixed=false;
-            }
+          m_Positions[aVertexId].m_Fixed=!m_Positions[aVertexId].m_Fixed;
         }
 
       m_CurrIter=1;
@@ -195,7 +192,10 @@ void FruchtermanReingold::MovePos(vertex_id_t aVertexId,const ImVec2& aDisp,bool
     }
 
   m_Positions[aVertexId].m_Pos+=aDisp;
-  m_Positions[aVertexId].m_Fixed=true;
+  if(sq_norm(aDisp)>0.0f)
+    {
+      m_Positions[aVertexId].m_Fixed=true;
+    }
 }
 
 
diff --git a/kamada_kawai.cpp b/kamada_kawai.cpp
index 19af54d..e4c56ec 100644
--- a/kamada_kawai.cpp
+++ b/kamada_kawai.cpp
@@ -337,10 +337,7 @@ void KamadaKawai::MovePos(vertex_id_t aVertexId,const ImVec2& aDisp,bool aRecalc
     {
       if(aDisp.x==kInvalidPos && aDisp.y==kInvalidPos)
         {
-          if(m_Positions[aVertexId].m_Fixed)
-            {
-              m_Positions[aVertexId].m_Fixed=false;
-            }
+          m_Positions[aVertexId].m_Fixed=!m_Positions[aVertexId].m_Fixed;
         }
 
       double energy=ComputeVertexEnergy(aVertexId);
@@ -356,7 +353,10 @@ void KamadaKawai::MovePos(vertex_id_t aVertexId,const ImVec2& aDisp,bool aRecalc
 
   ImVec2 disp=aDisp/m_Scale;
   m_Positions[aVertexId].m_Pos+=disp;
-  m_Positions[aVertexId].m_Fixed=true;
+  if(sq_norm(aDisp)>0.0f)
+    {
+      m_Positions[aVertexId].m_Fixed=true;
+    }
 }
 
 
diff --git a/nodesoup.hpp b/nodesoup.hpp
index 3839dbf..980de84 100644
--- a/nodesoup.hpp
+++ b/nodesoup.hpp
@@ -16,11 +16,20 @@ struct NsPosition
 
 constexpr float kInvalidPos=-1000000.0f;
 
+
 inline double norm(const ImVec2& aImVec2) noexcept
 {
   return sqrt(aImVec2.x * aImVec2.x + aImVec2.y * aImVec2.y);
 }
 
+inline float sq_norm(const ImVec2& aImVec2) noexcept
+{
+  return aImVec2.x*aImVec2.x + aImVec2.y*aImVec2.y;
+}
+
+
+
+
 namespace nodesoup
 {