diff --git a/code/library/src/main/kotlin/org/fbme/lib/iec61499/fbnetwork/FunctionBlockDeclarationBase.kt b/code/library/src/main/kotlin/org/fbme/lib/iec61499/fbnetwork/FunctionBlockDeclarationBase.kt
index fb794383a..78c69dd18 100644
--- a/code/library/src/main/kotlin/org/fbme/lib/iec61499/fbnetwork/FunctionBlockDeclarationBase.kt
+++ b/code/library/src/main/kotlin/org/fbme/lib/iec61499/fbnetwork/FunctionBlockDeclarationBase.kt
@@ -27,15 +27,14 @@ interface FunctionBlockDeclarationBase : Declaration, ContainedElement {
             return result
         }
 
-    fun getAllPorts(): List<FBPortDescriptor>  {
-        return type.eventInputPorts
+    fun getAllPorts(): List<FBPortDescriptor> =
+            type.eventInputPorts
                 .union(type.eventOutputPorts)
                 .union(type.dataInputPorts)
                 .union(type.dataOutputPorts)
                 .union(type.socketPorts)
                 .union(type.plugPorts)
                 .toList()
-    }
 
     var x: Int
     var y: Int
diff --git a/code/richediting/src/main/kotlin/org/fbme/ide/richediting/adapters/fbnetwork/FunctionBlockController.kt b/code/richediting/src/main/kotlin/org/fbme/ide/richediting/adapters/fbnetwork/FunctionBlockController.kt
index 42a295f24..79f90edf3 100644
--- a/code/richediting/src/main/kotlin/org/fbme/ide/richediting/adapters/fbnetwork/FunctionBlockController.kt
+++ b/code/richediting/src/main/kotlin/org/fbme/ide/richediting/adapters/fbnetwork/FunctionBlockController.kt
@@ -4,7 +4,6 @@ import jetbrains.mps.editor.runtime.style.CellAlign
 import jetbrains.mps.editor.runtime.style.Measure
 import jetbrains.mps.editor.runtime.style.Padding
 import jetbrains.mps.editor.runtime.style.StyleAttributes
-import jetbrains.mps.findUsages.FindUsagesManager
 import jetbrains.mps.nodeEditor.MPSColors
 import jetbrains.mps.nodeEditor.cellLayout.CellLayout_Vertical
 import jetbrains.mps.nodeEditor.cells.EditorCell
@@ -20,6 +19,9 @@ import org.fbme.ide.richediting.adapters.fbnetwork.fb.FBTypeCellComponent
 import org.fbme.ide.richediting.adapters.fbnetwork.fb.EditableFBTypeCell
 import org.fbme.ide.richediting.adapters.fbnetwork.port.PortActionFactory
 import org.fbme.ide.richediting.editor.RichEditorStyleAttributes
+import org.fbme.ide.richediting.utils.Notifier
+import org.fbme.ide.richediting.utils.ProjectProvider
+import org.fbme.ide.richediting.utils.fb.FBUsageFinder
 import org.fbme.ide.richediting.viewmodel.*
 import org.fbme.lib.iec61499.DeclarationsScope
 import org.fbme.lib.iec61499.IEC61499Factory
@@ -324,7 +326,21 @@ class FunctionBlockController(
             override fun executeInCommand(): Boolean = true
 
             override fun canExecute(context: EditorContext): Boolean {
-                //FindUsagesManager
+                val project = ProjectProvider.getInstance(context)!!
+                val res = FBUsageFinder
+                        .findUsages(project, view.component.type.declaration!!)
+                        .filter {
+                            it.key.identifier != networkInstance.declaration.identifier
+                        }.map {
+                            it.key
+                        }
+                if (res.isNotEmpty()) {
+                    Notifier.showWarning(
+                            "This function block uses also in " +
+                            res.joinToString { it.name } + "!",
+                            project.project
+                    )
+                }
                 return true
             }
 
diff --git a/code/richediting/src/main/kotlin/org/fbme/ide/richediting/utils/fb/FBUsageFinder.kt b/code/richediting/src/main/kotlin/org/fbme/ide/richediting/utils/fb/FBUsageFinder.kt
new file mode 100644
index 000000000..9c531caf1
--- /dev/null
+++ b/code/richediting/src/main/kotlin/org/fbme/ide/richediting/utils/fb/FBUsageFinder.kt
@@ -0,0 +1,31 @@
+package org.fbme.ide.richediting.utils.fb
+
+import jetbrains.mps.findUsages.FindUsagesManager
+import jetbrains.mps.project.MPSProject
+import org.fbme.ide.iec61499.repository.PlatformElement
+import org.fbme.ide.iec61499.repository.PlatformRepositoryProvider
+import org.fbme.lib.common.Declaration
+import org.jetbrains.mps.openapi.model.SNode
+
+object FBUsageFinder {
+    fun findUsages(project: MPSProject,  fbBlock: Declaration)
+    : Map<Declaration, SNode> {
+        val manager = project.getComponent(FindUsagesManager::class.java)
+        val platformElement = (fbBlock as PlatformElement)
+        val nodes = manager.findUsages(project.scope, mutableSetOf(platformElement.node), null)
+        val repository = PlatformRepositoryProvider.getInstance(project)
+
+        val result: MutableMap<Declaration, SNode> = HashMap()
+        nodes.mapNotNull {
+            it.sourceNode.parent
+        }.forEach {
+            val declaration = repository.getAdapter(it, Declaration::class.java)
+
+            if (declaration != null) {
+                result[declaration] = it
+            }
+        }
+
+        return result
+    }
+}