diff --git a/src/com/exedio/cope/console/CharacterNulCop.java b/src/com/exedio/cope/console/CharacterNulCop.java
index 7492ab6e..5dac93f0 100644
--- a/src/com/exedio/cope/console/CharacterNulCop.java
+++ b/src/com/exedio/cope/console/CharacterNulCop.java
@@ -83,12 +83,6 @@ List<StringField> getItems()
 		return result;
 	}
 
-	@Override
-	int getNumberOfFilterableColumns()
-	{
-		return 1;
-	}
-
 	@Override
 	List<Column<StringField>> columns()
 	{
@@ -97,7 +91,7 @@ List<Column<StringField>> columns()
 
 	private static final List<Column<StringField>> COLUMNS = List.of(
 			column("Field", StringField::getID),
-			column("CharSet", (out, field) ->
+			columnNonFilterable("CharSet", (out, field) ->
 			{
 				final CharSet charSet = field.getCharSet();
 				if(charSet!=null)
diff --git a/src/com/exedio/cope/console/FeatureFieldCop.java b/src/com/exedio/cope/console/FeatureFieldCop.java
index 70e8b902..e3a45dc2 100644
--- a/src/com/exedio/cope/console/FeatureFieldCop.java
+++ b/src/com/exedio/cope/console/FeatureFieldCop.java
@@ -105,7 +105,7 @@ List<Column<FeatureField<?>>> columns()
 	private static final List<Column<FeatureField<?>>> COLUMNS = List.of(
 			column("Type", field -> field.getType().getID()),
 			column("Name", field -> field.getName()),
-			column("Values", (out, field) -> writeValueLong(out, field.getValues().toString()))
+			columnNonFilterable("Values", (out, field) -> writeValueLong(out, field.getValues().toString()))
 	);
 
 	@Override
diff --git a/src/com/exedio/cope/console/HashConstraintCop.java b/src/com/exedio/cope/console/HashConstraintCop.java
index 45a615c4..579daa5d 100644
--- a/src/com/exedio/cope/console/HashConstraintCop.java
+++ b/src/com/exedio/cope/console/HashConstraintCop.java
@@ -84,12 +84,6 @@ List<HashConstraint> getItems()
 		return result;
 	}
 
-	@Override
-	int getNumberOfFilterableColumns()
-	{
-		return 1;
-	}
-
 	@Override
 	List<Column<HashConstraint>> columns()
 	{
@@ -109,13 +103,13 @@ List<Column<HashConstraint>> columns()
 				if(pattern instanceof Media)
 					out.writeRaw("</a>");
 			}),
-			column("Content Type", (out, constraint) ->
+			columnNonFilterable("Content Type", (out, constraint) ->
 			{
 				final Pattern pattern = constraint.getData().getPattern();
 				if(pattern instanceof Media)
 					out.write(((Media)pattern).getContentTypeDescription().replaceAll(",", ", "));
 			}),
-			column("Hash", (out, constraint) ->
+			columnNonFilterable("Hash", (out, constraint) ->
 			{
 				final String algorithm = constraint.getAlgorithm();
 				out.write(algorithm);
@@ -124,7 +118,7 @@ List<Column<HashConstraint>> columns()
 						model.isConnected() &&
 						!model.getSupportedDataHashAlgorithms().contains(algorithm));
 			}),
-			column("SQL", (out, constraint) ->
+			columnNonFilterable("SQL", (out, constraint) ->
 			{
 				final Query<?> query = getQuery(constraint);
 				if(!query.getType().getModel().isConnected())
diff --git a/src/com/exedio/cope/console/MediaTestableCop.java b/src/com/exedio/cope/console/MediaTestableCop.java
index b161af0e..2f2ac1fd 100644
--- a/src/com/exedio/cope/console/MediaTestableCop.java
+++ b/src/com/exedio/cope/console/MediaTestableCop.java
@@ -71,12 +71,6 @@ List<MediaTestable> getItems()
 		return result;
 	}
 
-	@Override
-	int getNumberOfFilterableColumns()
-	{
-		return 3;
-	}
-
 	@Override
 	List<Column<MediaTestable>> columns()
 	{
diff --git a/src/com/exedio/cope/console/MediaTypeCop.java b/src/com/exedio/cope/console/MediaTypeCop.java
index 53c2fb7d..277efc57 100644
--- a/src/com/exedio/cope/console/MediaTypeCop.java
+++ b/src/com/exedio/cope/console/MediaTypeCop.java
@@ -101,8 +101,8 @@ List<Column<Media>> columns()
 				out.write(media.getName());
 				out.writeRaw("</a>");
 			}),
-			column("Content Type", media -> media.getContentTypeDescription().replaceAll(",", ", ")),
-			column("Query", (out, media) ->
+			columnNonFilterable("Content Type", media -> media.getContentTypeDescription().replaceAll(",", ", ")),
+			columnNonFilterable("Query", (out, media) ->
 			{
 				final Condition c = media.bodyMismatchesContentTypeIfSupported();
 				if(c!=Condition.FALSE)
diff --git a/src/com/exedio/cope/console/MinLengthStringFieldCop.java b/src/com/exedio/cope/console/MinLengthStringFieldCop.java
index 3a95fb85..12c09aaf 100644
--- a/src/com/exedio/cope/console/MinLengthStringFieldCop.java
+++ b/src/com/exedio/cope/console/MinLengthStringFieldCop.java
@@ -62,12 +62,6 @@ List<StringField> getItems()
 		return result;
 	}
 
-	@Override
-	int getNumberOfFilterableColumns()
-	{
-		return 1;
-	}
-
 	@Override
 	List<Column<StringField>> columns()
 	{
@@ -76,7 +70,7 @@ List<Column<StringField>> columns()
 
 	private static final List<Column<StringField>> COLUMNS = List.of(
 			column("Field", StringField::toString),
-			column("Min Length", field -> Format.formatAndHide(0, field.getMinimumLength()))
+			columnNonFilterable("Min Length", field -> Format.formatAndHide(0, field.getMinimumLength()))
 	);
 
 	@Override
diff --git a/src/com/exedio/cope/console/SequenceCop.java b/src/com/exedio/cope/console/SequenceCop.java
index 0882051b..767fbed2 100644
--- a/src/com/exedio/cope/console/SequenceCop.java
+++ b/src/com/exedio/cope/console/SequenceCop.java
@@ -96,12 +96,12 @@ List<Column<SequenceInfo>> columns()
 	private static final List<Column<SequenceInfo>> COLUMNS = List.of(
 			column("Type", info -> info.getFeature().getType().getID()),
 			column("Name", info -> info.getFeature().getName()),
-			column("Start", info -> format(info.getStartL())),
-			column("Min",   info -> format(info.getMinimumL())),
-			column("Max",   info -> format(info.getMaximumL())),
-			column("Count", info -> format(info.getCountL())),
-			column("First", (out, info) -> { if(info.isKnown()) out.write(format(info.getFirstL())); }),
-			column("Last",  (out, info) -> { if(info.isKnown()) out.write(format(info.getLastL()));  })
+			columnNonFilterable("Start", info -> format(info.getStartL())),
+			columnNonFilterable("Min",   info -> format(info.getMinimumL())),
+			columnNonFilterable("Max",   info -> format(info.getMaximumL())),
+			columnNonFilterable("Count", info -> format(info.getCountL())),
+			columnNonFilterable("First", (out, info) -> { if(info.isKnown()) out.write(format(info.getFirstL())); }),
+			columnNonFilterable("Last",  (out, info) -> { if(info.isKnown()) out.write(format(info.getLastL()));  })
 	);
 
 	@Override
diff --git a/src/com/exedio/cope/console/Test.jspm b/src/com/exedio/cope/console/Test.jspm
index 10308f71..439d581b 100644
--- a/src/com/exedio/cope/console/Test.jspm
+++ b/src/com/exedio/cope/console/Test.jspm
@@ -288,7 +288,7 @@ final class Test_Jspm
 				%>
 				<th>
 					<%=column.heading%>
-					<%if (i<cop.getNumberOfFilterableColumns()) { %>
+					<%if (column.filterable) { %>
 						<input class="filter" type="text" onkeyup="filterRows(this.value, <%=i%>);" placeholder="Filter"></input>
 					<%}%>
 					</th><%
diff --git a/src/com/exedio/cope/console/TestCop.java b/src/com/exedio/cope/console/TestCop.java
index 3b5fc2d8..c93abf59 100644
--- a/src/com/exedio/cope/console/TestCop.java
+++ b/src/com/exedio/cope/console/TestCop.java
@@ -449,11 +449,6 @@ String getNoItemsMessage()
 		return "There are no "+name+" in this model.";
 	}
 
-	int getNumberOfFilterableColumns()
-	{
-		return 2;
-	}
-
 	final String getViolationSqlIfConnected(final I item)
 	{
 		try
@@ -479,23 +474,43 @@ String getViolationSql(final I item)
 
 	static final <I> Column<I> column(final String heading, final Function<I,String> cell)
 	{
-		return new Column<>(heading, (out, field) -> out.write(cell.apply(field)));
+		return new Column<>(heading, toConsumer(cell), true);
+	}
+
+	// TODO
+	// I'd rather want to have a modifier method Column#nonFilterable,
+	// but this causes compiler errors I don't understand.
+	static final <I> Column<I> columnNonFilterable(final String heading, final Function<I,String> cell)
+	{
+		return new Column<>(heading, toConsumer(cell), false);
+	}
+
+	private static <I> BiConsumer<Out, I> toConsumer(final Function<I,String> cell)
+	{
+		return (out, field) -> out.write(cell.apply(field));
 	}
 
 	static final <I> Column<I> column(final String heading, final BiConsumer<Out, I> cell)
 	{
-		return new Column<>(heading, cell);
+		return new Column<>(heading, cell, true);
+	}
+
+	static final <I> Column<I> columnNonFilterable(final String heading, final BiConsumer<Out, I> cell)
+	{
+		return new Column<>(heading, cell, false);
 	}
 
 	protected static final class Column<I>
 	{
 		final String heading;
 		final BiConsumer<Out, I> cell;
+		final boolean filterable;
 
-		Column(final String heading, final BiConsumer<Out, I> cell)
+		Column(final String heading, final BiConsumer<Out, I> cell, final boolean filterable)
 		{
 			this.heading = requireNonNull(heading);
 			this.cell = requireNonNull(cell);
+			this.filterable = filterable;
 		}
 	}
 
diff --git a/src/com/exedio/cope/console/TypeFieldCop.java b/src/com/exedio/cope/console/TypeFieldCop.java
index 4773915f..4a7c1d2f 100644
--- a/src/com/exedio/cope/console/TypeFieldCop.java
+++ b/src/com/exedio/cope/console/TypeFieldCop.java
@@ -105,7 +105,7 @@ List<Column<TypeField<?>>> columns()
 	private static final List<Column<TypeField<?>>> COLUMNS = List.of(
 			column("Type", field -> field.getType().getID()),
 			column("Name", field -> field.getName()),
-			column("Values", (out, field) -> writeValueLong(out, field.getValues().toString()))
+			columnNonFilterable("Values", (out, field) -> writeValueLong(out, field.getValues().toString()))
 	);
 
 	@Override
diff --git a/src/com/exedio/cope/console/UnsupportedCheckConstraintByTableCop.java b/src/com/exedio/cope/console/UnsupportedCheckConstraintByTableCop.java
index 64898535..26cd6c7e 100644
--- a/src/com/exedio/cope/console/UnsupportedCheckConstraintByTableCop.java
+++ b/src/com/exedio/cope/console/UnsupportedCheckConstraintByTableCop.java
@@ -106,12 +106,6 @@ List<Table> getItems()
 		return result;
 	}
 
-	@Override
-	int getNumberOfFilterableColumns()
-	{
-		return 1;
-	}
-
 	UnsupportedConstraintCop toTable(final Table table)
 	{
 		return new UnsupportedConstraintCop(args, testArgs, table.getName());
@@ -122,7 +116,7 @@ List<Column<Table>> columns()
 	{
 		return List.of(
 			column("Table", (out, table) -> UnsupportedCheckConstraintByTable_Jspm.writeTableValue(this, out, table)),
-			column("Condition", (out, table) ->
+			columnNonFilterable("Condition", (out, table) ->
 			{
 				final StringBuilder bf = new StringBuilder();
 				appendSQL(table, bf);
diff --git a/src/com/exedio/cope/console/UnsupportedConstraintCop.java b/src/com/exedio/cope/console/UnsupportedConstraintCop.java
index a05664bb..00862bcb 100644
--- a/src/com/exedio/cope/console/UnsupportedConstraintCop.java
+++ b/src/com/exedio/cope/console/UnsupportedConstraintCop.java
@@ -120,7 +120,7 @@ List<Column<Constraint>> columns()
 	private static final List<Column<Constraint>> COLUMNS = List.of(
 			column("Table", constraint -> constraint.getTable().getName()),
 			column("Name",  constraint -> constraint.getName()),
-			column("Condition", (out, constraint) -> writeValueLong(out, constraint.getRequiredCondition()))
+			columnNonFilterable("Condition", (out, constraint) -> writeValueLong(out, constraint.getRequiredCondition()))
 	);
 
 	@Override