diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/OrganizeIncludesBlock.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/OrganizeIncludesBlock.java
index f16087f9a9b..c82bfe53231 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/OrganizeIncludesBlock.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/preferences/OrganizeIncludesBlock.java
@@ -73,22 +73,22 @@ public class OrganizeIncludesBlock extends OptionsConfigurationBlock {
 		composite.setLayout(layout);
 
 		Control control = addCheckBox(composite, PreferencesMessages.OrganizeIncludesBlock_allow_reordering,
-				KEY_INCLUDES_REORDERING, FALSE_TRUE, 0);
+				KEY_INCLUDES_REORDERING, TRUE_FALSE, 0);
 		LayoutUtil.setHorizontalSpan(control, 2);
 		control = addCheckBox(composite, PreferencesMessages.OrganizeIncludesBlock_heuristic_header_substitution,
-				KEY_HEURISTIC_HEADER_SUBSTITUTION, FALSE_TRUE, 0);
+				KEY_HEURISTIC_HEADER_SUBSTITUTION, TRUE_FALSE, 0);
 		LayoutUtil.setHorizontalSpan(control, 2);
 		control = addCheckBox(composite, PreferencesMessages.OrganizeIncludesBlock_forward_declare_composite_types,
-				KEY_FORWARD_DECLARE_COMPOSITE_TYPES, FALSE_TRUE, 0);
+				KEY_FORWARD_DECLARE_COMPOSITE_TYPES, TRUE_FALSE, 0);
 		LayoutUtil.setHorizontalSpan(control, 2);
 		control = addCheckBox(composite, PreferencesMessages.OrganizeIncludesBlock_forward_declare_enums,
-				KEY_FORWARD_DECLARE_ENUMS, FALSE_TRUE, 0);
+				KEY_FORWARD_DECLARE_ENUMS, TRUE_FALSE, 0);
 		LayoutUtil.setHorizontalSpan(control, 2);
 		control = addCheckBox(composite, PreferencesMessages.OrganizeIncludesBlock_forward_declare_functions,
-				KEY_FORWARD_DECLARE_FUNCTIONS, FALSE_TRUE, 0);
+				KEY_FORWARD_DECLARE_FUNCTIONS, TRUE_FALSE, 0);
 		LayoutUtil.setHorizontalSpan(control, 2);
 		control = addCheckBox(composite, PreferencesMessages.OrganizeIncludesBlock_forward_declare_namespace_elements,
-				KEY_FORWARD_DECLARE_NAMESPACE_ELEMENTS, FALSE_TRUE, 0);
+				KEY_FORWARD_DECLARE_NAMESPACE_ELEMENTS, TRUE_FALSE, 0);
 		LayoutUtil.setHorizontalSpan(control, 2);
 		control = addComboBox(composite, PreferencesMessages.OrganizeIncludesBlock_unused_statements,
 				KEY_UNUSED_STATEMENTS_DISPOSITION, DISPOSITION_VALUES, DISPOSITION_LABELS, 0);
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludeOrganizer.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludeOrganizer.java
index 6e4da24f873..87f92b7f119 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludeOrganizer.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludeOrganizer.java
@@ -288,12 +288,18 @@ public class IncludeOrganizer {
 		}
 
 		List<String> includeDirectives = new ArrayList<String>();
+		IncludeGroupStyle previousParentStyle = null;
 		for (List<IPath> headers : orderedHeaders) {
 			if (headers != null && !headers.isEmpty()) {
 				Collections.sort(headers, PATH_COMPARATOR);
 				IncludeGroupStyle style = classifiedHeaders.get(headers.get(0));
 				IncludeGroupStyle groupingStyle = getGroupingStyle(style);
-				if (!includeDirectives.isEmpty() && groupingStyle.isBlankLineBefore())
+				IncludeGroupStyle parentStyle = getParentStyle(groupingStyle);
+				boolean blankLineBefore = groupingStyle.isBlankLineBefore() ||
+						(parentStyle != null && parentStyle != previousParentStyle &&
+						parentStyle.isKeepTogether() && parentStyle.isBlankLineBefore());
+				previousParentStyle = parentStyle;
+				if (!includeDirectives.isEmpty() && blankLineBefore)
 					includeDirectives.add(""); // Blank line separator //$NON-NLS-1$
 				for (IPath header : headers) {
 					style = classifiedHeaders.get(header);
@@ -335,15 +341,19 @@ public class IncludeOrganizer {
 	private IncludeGroupStyle getGroupingStyle(IncludeGroupStyle style) {
 		if (style.isKeepTogether())
 			return style;
-		IncludeKind kind = style.getIncludeKind().parent;
-		if (kind != null) {
-			IncludeGroupStyle parent = fContext.getPreferences().includeStyles.get(kind);
-			if (parent != null && (parent.isKeepTogether() || parent.getIncludeKind() == IncludeKind.OTHER))
-				return parent;
-		}
+		IncludeGroupStyle parent = getParentStyle(style);
+		if (parent != null && (parent.isKeepTogether() || parent.getIncludeKind() == IncludeKind.OTHER))
+			return parent;
 		return fContext.getPreferences().includeStyles.get(IncludeKind.OTHER);
 	}
 
+	private IncludeGroupStyle getParentStyle(IncludeGroupStyle style) {
+		IncludeKind kind = style.getIncludeKind().parent;
+		if (kind == null)
+			return null;
+		return fContext.getPreferences().includeStyles.get(kind);
+	}
+
 	private IncludeGroupStyle getIncludeStyle(IPath headerPath) {
 		IncludeKind includeKind;
 		IncludeInfo includeInfo = fContext.getIncludeForHeaderFile(headerPath);
diff --git a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludePreferences.java b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludePreferences.java
index 03a06f8ac02..3a7fb38653e 100644
--- a/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludePreferences.java
+++ b/core/org.eclipse.cdt.ui/src/org/eclipse/cdt/internal/ui/refactoring/includes/IncludePreferences.java
@@ -54,6 +54,8 @@ public class IncludePreferences {
 		loadStyle(IncludeKind.IN_SAME_PROJECT, PREF_INCLUDE_STYLE_SAME_PROJECT, project);
 		loadStyle(IncludeKind.IN_OTHER_PROJECT, PREF_INCLUDE_STYLE_OTHER_PROJECT, project);
 		loadStyle(IncludeKind.EXTERNAL, PREF_INCLUDE_STYLE_EXTERNAL, project);
+		// Unclassified includes are always kept together.
+		includeStyles.get(IncludeKind.OTHER).setKeepTogether(true);
 		// Normalize order property of the styles to make sure that the numbers are sequential.
 		List<IncludeGroupStyle> styles = new ArrayList<IncludeGroupStyle>(includeStyles.values());
 		Collections.sort(styles);