diff --git a/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheck.cs b/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheck.cs
index f4014249c1..c335ad3174 100644
--- a/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheck.cs
+++ b/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheck.cs
@@ -14,30 +14,40 @@ namespace SharpRefactoring.ContextActions
 	{
 		public override bool IsAvailable(EditorContext context)
 		{
-			var paramAtCaret = GetParameterAtCaret(context.CurrentSymbol);
+			var paramAtCaret = GetParameterAtCaret(context);
 			if (paramAtCaret == null)
 				return false;
 			
 			return IsAvailable(paramAtCaret.ResolvedType);
 		}
 		
-		public LocalResolveResult GetParameterAtCaret(ResolveResult symbol)
+		public LocalResolveResult GetParameterAtCaret(EditorContext context)
 		{
-			LocalResolveResult param = symbol as LocalResolveResult;
-			if (param == null || param.CallingClass == null || param.ResolvedType == null)
+			LocalResolveResult paramAtCaret = context.CurrentSymbol as LocalResolveResult;
+			if (paramAtCaret == null || paramAtCaret.CallingClass == null || paramAtCaret.ResolvedType == null)
 				return null;
-			if (param.CallingClass.ProjectContent.Language != LanguageProperties.CSharp)
+			// only for C#
+			if (paramAtCaret.CallingClass.ProjectContent.Language != LanguageProperties.CSharp)
 				return null;
-			if (!param.IsParameter)
+			if (!paramAtCaret.IsParameter)
 				return null;
-			// FIXME must be parameter definition, and method with body (not interface or abstract)
-			return param;
+			// must be definition
+			if (!paramAtCaret.VariableDefinitionRegion.IsInside(context.CurrentExpression.Region.BeginLine, context.CurrentExpression.Region.BeginColumn))
+				return null;
+			// must be not abstract/interface method
+			if (paramAtCaret.CallingMember == null || paramAtCaret.CallingMember.IsAbstract || 
+			    paramAtCaret.CallingMember.DeclaringType.ClassType == ClassType.Interface)
+				return null;
+			return paramAtCaret;
 		}
-			
+		
 		public override void Execute(EditorContext context)
 		{
-			var paramAtCaret = GetParameterAtCaret(context.CurrentSymbol);
-			Extensions.AddCodeToMethodStart(paramAtCaret.CallingMember, context.Editor, GetCodeToInsert(paramAtCaret.VariableName));
+			var paramAtCaret = GetParameterAtCaret(context);
+			if (paramAtCaret != null)
+			{
+				Extensions.AddCodeToMethodStart(paramAtCaret.CallingMember, context.Editor, GetCodeToInsert(paramAtCaret.VariableName));
+			}
 		}
 		
 		public abstract bool IsAvailable(IReturnType parameterType);
diff --git a/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheckForNull.cs b/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheckForNull.cs
index dfbe51706f..df72a5ec6e 100644
--- a/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheckForNull.cs
+++ b/src/AddIns/Misc/SharpRefactoring/Project/Src/ContextActions/ParamCheckForNull.cs
@@ -19,7 +19,8 @@ namespace SharpRefactoring.ContextActions
 		public override bool IsAvailable(IReturnType parameterType)
 		{
 			var parameterTypeClass = parameterType.GetUnderlyingClass();
-			return (parameterTypeClass == null || parameterTypeClass.ClassType != ClassType.Enum && parameterTypeClass.ClassType != ClassType.Struct);
+			return (parameterTypeClass == null || 
+			        (parameterTypeClass.ClassType != ClassType.Enum && parameterTypeClass.ClassType != ClassType.Struct));
 		}
 		
 		public override string GetCodeToInsert(string parameterName)
diff --git a/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Interfaces/IEntity.cs b/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Interfaces/IEntity.cs
index b2fa729907..5fdb21f499 100644
--- a/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Interfaces/IEntity.cs
+++ b/src/Main/ICSharpCode.SharpDevelop.Dom/Project/Src/Interfaces/IEntity.cs
@@ -49,6 +49,10 @@ namespace ICSharpCode.SharpDevelop.Dom
 			get;
 		}
 
+		/// <summary>
+		/// Returns true if this entity has the 'abstract' modifier set. 
+		/// (Returns false for interface members).
+		/// </summary>
 		bool IsAbstract {
 			get;
 		}