diff --git a/src/SIL.LCModel/DomainImpl/OverridesCellar.cs b/src/SIL.LCModel/DomainImpl/OverridesCellar.cs
index 40599fe1..e32fa6d0 100644
--- a/src/SIL.LCModel/DomainImpl/OverridesCellar.cs
+++ b/src/SIL.LCModel/DomainImpl/OverridesCellar.cs
@@ -2247,8 +2247,9 @@ public ITsString GetFeatureValueString(bool fLongForm)
 			var tisb = TsStringUtils.MakeIncStrBldr();
 			tisb.SetIntPropValues((int)FwTextPropType.ktptWs, (int)FwTextPropVar.ktpvDefault, Cache.DefaultUserWs);
 
-			var sFeature = GetFeatureString(fLongForm);
-			var sValue = GetValueString(fLongForm);
+			// ValueRA == null is an empty value that is filled in by FillInBlanks.
+			var sFeature = GetFeatureString(fLongForm || ValueRA == null);
+			var sValue = ValueRA == null ? "*" : GetValueString(fLongForm);
 			if ((!fLongForm) &&
 				(FeatureRA != null) &&
 				(FeatureRA.DisplayToRightOfValues))
@@ -3871,8 +3872,8 @@ from myitem in FeatureSpecsOC
 				else
 				{
 					if (myFeatureValues.First() is IFsComplexValue complex &&
-					    spec is IFsComplexValue newComplexValue &&
-					    complex.ValueOA is IFsFeatStruc fs)
+						spec is IFsComplexValue newComplexValue &&
+						complex.ValueOA is IFsFeatStruc fs)
 					{
 						fs.PriorityUnion(newComplexValue.ValueOA as IFsFeatStruc);
 					}
@@ -3885,6 +3886,87 @@ spec is IFsComplexValue newComplexValue &&
 			}
 
 		}
+
+		/// <summary>
+		/// Fill in the blanks.
+		/// Remove unfilled blanks and empty feature structures.
+		/// </summary>
+		/// <param name="fsValue">the values to fill with</param>
+		public IFsFeatStruc FillInBlanks(IFsFeatStruc fsValue)
+		{
+			foreach (IFsFeatureSpecification spec in FeatureSpecsOC.ToList())
+			{
+				// Find matching specification.
+				IFsFeatureSpecification spec2 = null;
+				if (fsValue != null)
+				{
+					foreach (var spec3 in fsValue.FeatureSpecsOC)
+					{
+						if (spec3.FeatureRA.Name == spec.FeatureRA.Name)
+						{
+							spec2 = spec3;
+						}
+					}
+				}
+				// Fill in blanks in spec.
+				if (spec is IFsClosedValue closed && closed != null && closed.ValueRA == null)
+				{
+					if (spec2 is IFsClosedValue closed2 && closed2 != null)
+					{
+						// Fill in blank.
+						closed.ValueRA = closed2.ValueRA;
+
+					}
+					if (closed.ValueRA == null)
+					{
+						// Remove unfilled blank.
+						FeatureSpecsOC.Remove(spec);
+					}
+				}
+				if (spec is IFsComplexValue complex && complex != null)
+				{
+					// Recursively fill in blanks.
+					if (complex.ValueOA is IFsFeatStruc fs)
+					{
+						IFsComplexValue complex2 = spec2 as IFsComplexValue;
+						if (fs.FillInBlanks(complex2?.ValueOA as IFsFeatStruc) == null)
+						{
+							// Remove empty feature structure.
+							FeatureSpecsOC.Remove(complex);
+						}
+					}
+				}
+			}
+			// See if removing blanks emptied the feature structure.
+			if (FeatureSpecsOC.Count == 0)
+			{
+				return null;
+			}
+			return this;
+		}
+
+		public bool ContainsBlank()
+		{
+			foreach (IFsFeatureSpecification spec in FeatureSpecsOC.ToList())
+			{
+				if (spec is IFsClosedValue closed && closed != null && closed.ValueRA == null)
+				{
+					return true;
+				}
+				if (spec is IFsComplexValue complex && complex != null)
+				{
+					if (complex.ValueOA is IFsFeatStruc fs)
+					{
+						if (fs.ContainsBlank())
+						{
+							return true;
+						}
+					}
+				}
+			}
+			return false;
+		}
+
 		protected override void RemoveObjectSideEffectsInternal(RemoveObjectEventArgs e)
 		{
 			switch (e.Flid)
diff --git a/src/SIL.LCModel/InterfaceAdditions.cs b/src/SIL.LCModel/InterfaceAdditions.cs
index d10bd041..e0de10d8 100644
--- a/src/SIL.LCModel/InterfaceAdditions.cs
+++ b/src/SIL.LCModel/InterfaceAdditions.cs
@@ -2323,6 +2323,19 @@ ITsString LongNameSortedTSS
 		/// </summary>
 		/// <param name="fsNew">the new feature structure</param>
 		void PriorityUnion(IFsFeatStruc fsNew);
+
+		/// <summary>
+		/// Fill in the blanks of this feature structure
+		/// using the given values.
+		/// Eliminates blanks with no values and returns null if there is nothing left.
+		/// </summary>
+		/// <param name="fsValues">feature structure with given values</param>
+		IFsFeatStruc FillInBlanks(IFsFeatStruc fsValues);
+
+		/// <summary>
+		/// Determine if this feature structure contains a blank.
+		/// </summary>
+		public bool ContainsBlank();
 	}
 
 	/// <summary>
diff --git a/tests/SIL.LCModel.Tests/DomainImpl/CellarTests.cs b/tests/SIL.LCModel.Tests/DomainImpl/CellarTests.cs
index abc0ba07..b232f3c4 100644
--- a/tests/SIL.LCModel.Tests/DomainImpl/CellarTests.cs
+++ b/tests/SIL.LCModel.Tests/DomainImpl/CellarTests.cs
@@ -459,6 +459,22 @@ public void AddClosedFeaturesToFeatureSystemAndThenToAFeatureStructure()
 				Assert.AreEqual("Gen", cv.FeatureRA.Abbreviation.AnalysisDefaultWritingSystem.Text, "Expect to have Gen feature name");
 				Assert.AreEqual("Neut", cv.ValueRA.Abbreviation.AnalysisDefaultWritingSystem.Text, "Expect to have Neut feature value");
 			}
+
+			// Test FillInBlanks.
+			IFsClosedValue closedValue = featStruct.FeatureSpecsOC.First() as IFsClosedValue;
+			closedValue.ValueRA = null;
+			Assert.AreEqual("Gen:*", featStruct.ShortName);
+			Assert.IsTrue(featStruct.ContainsBlank());
+			Assert.IsFalse(featStrucGenNeut.ContainsBlank());
+			featStruct = featStruct.FillInBlanks(featStrucGenNeut);
+			Assert.IsFalse(featStruct.ContainsBlank());
+			Assert.AreEqual("Agr", featStruct.TypeRA.Abbreviation.AnalysisDefaultWritingSystem.Text, "Expect type Agr");
+			Assert.AreEqual(1, featStruct.FeatureSpecsOC.Count, "should have one feature spec");
+			foreach (IFsClosedValue cv in featStruct.FeatureSpecsOC)
+			{
+				Assert.AreEqual("Gen", cv.FeatureRA.Abbreviation.AnalysisDefaultWritingSystem.Text, "Expect to have Gen feature name");
+				Assert.AreEqual("Neut", cv.ValueRA.Abbreviation.AnalysisDefaultWritingSystem.Text, "Expect to have Neut feature value");
+			}
 		}
 
 		/// ------------------------------------------------------------------------------------
@@ -667,6 +683,31 @@ public void AddComplexFeaturesToFeatureSystemAndThenToAFeatureStructure()
 			// Check for correct LongName
 			Assert.AreEqual("[asp:aor sbj:[gen:n num:sg pers:1]]", featStruct.LongName, "Incorrect LongName for merged feature struture");
 			Assert.AreEqual("[asp:aor sbj:[gen:n num:sg pers:1]]", featStruct.LongNameSorted, "Incorrect LongNameSorted for merged feature struture");
+
+			// Test FillInBlanks.
+			pos.DefaultFeaturesOA = null;
+			pos.DefaultFeaturesOA = Cache.ServiceLocator.GetInstance<IFsFeatStrucFactory>().Create();
+			featStruct = pos.DefaultFeaturesOA;
+			featStruct.AddFeatureFromXml(itemFem, msfs);
+			IFsComplexValue complexValue = featStruct.FeatureSpecsOC.First() as IFsComplexValue;
+			IFsFeatStruc fsValue = complexValue.ValueOA as IFsFeatStruc;
+			IFsClosedValue closedValue = fsValue.FeatureSpecsOC.First() as IFsClosedValue;
+			closedValue.ValueRA = null;
+			Assert.AreEqual("gen:*", featStruct.ShortName);
+			Assert.IsTrue(featStruct.ContainsBlank());
+			Assert.IsFalse(featStruct2.ContainsBlank());
+			featStruct = featStruct.FillInBlanks(featStruct2);
+			Assert.IsFalse(featStruct2.ContainsBlank());
+			Assert.AreEqual("[sbj:[gen:n]]", featStruct.LongName, "Incorrect LongName for merged feature struture");
+
+			// Test removing FillInBlanks.
+			closedValue.ValueRA = null;
+			featStruct2.FeatureSpecsOC.Remove(featStruct2.FeatureSpecsOC.First());
+			Assert.AreEqual("gen:*", featStruct.ShortName);
+			Assert.IsTrue(featStruct.ContainsBlank());
+			Assert.IsFalse(featStruct2.ContainsBlank());
+			featStruct = featStruct.FillInBlanks(featStruct2);
+			Assert.AreEqual(null, featStruct, "FillInBlanks didn't remove unfilled blanks");
 		}