diff --git a/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkEditCmd.java b/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkEditCmd.java
index 504de20dfe..6f7f9aa948 100644
--- a/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkEditCmd.java
+++ b/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkEditCmd.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -41,8 +41,8 @@ public class BookmarkEditCmd implements Command<Program> {
 	private String presentationName;
 
 	/**
-	 * Edit a Bookmark. When editing a bookmark, all fields are used except the address
-	 * which is determined by the first address within each range of the set.
+	 * Constructor
+	 * 
 	 * @param set list of bookmark addresses.
 	 * @param type the bookmark type.
 	 * @param category the bookmark category.
@@ -53,14 +53,15 @@ public class BookmarkEditCmd implements Command<Program> {
 		this.category = category;
 		this.comment = comment;
 		this.set = set;
-		if (set == null || set.isEmpty() || type == null || type.length() == 0)
+		if (set == null || set.isEmpty() || type == null || type.length() == 0) {
 			throw new IllegalArgumentException();
+		}
 		presentationName = "Add " + type + " Bookmark(s)";
 	}
 
 	/**
-	 * Edit a Bookmark. When editing a bookmark, all fields are used except the address
-	 * which is provided by the addrs parameter.
+	 * Constructor
+	 * 
 	 * @param addr the bookmark address.
 	 * @param type the bookmark type.
 	 * @param category the bookmark category.
@@ -71,8 +72,9 @@ public class BookmarkEditCmd implements Command<Program> {
 		this.category = category;
 		this.comment = comment;
 		this.addr = addr;
-		if (addr == null || type == null || type.length() == 0)
+		if (addr == null || type == null || type.length() == 0) {
 			throw new IllegalArgumentException();
+		}
 		presentationName = "Add " + type + " Bookmark";
 	}
 
@@ -80,13 +82,14 @@ public class BookmarkEditCmd implements Command<Program> {
 		this.bookmark = bookmark;
 		this.category = category;
 		this.comment = comment;
-		if (bookmark == null)
+		if (bookmark == null) {
 			throw new IllegalArgumentException();
+		}
 		presentationName = "Edit " + bookmark.getTypeString() + " Bookmark";
 	}
 
 	/**
-	 * The name of the edit action.
+	 * {@return The name of the edit action.}
 	 */
 	public String getPresentationName() {
 		return presentationName;
diff --git a/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkNavigator.java b/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkNavigator.java
index bf29ce1268..33d123b09d 100644
--- a/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkNavigator.java
+++ b/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkNavigator.java
@@ -4,9 +4,9 @@
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
  * You may obtain a copy of the License at
- * 
+ *
  *      http://www.apache.org/licenses/LICENSE-2.0
- * 
+ *
  * Unless required by applicable law or agreed to in writing, software
  * distributed under the License is distributed on an "AS IS" BASIS,
  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
@@ -82,7 +82,11 @@ public class BookmarkNavigator {
 
 		Icon icon = bmt.getIcon();
 		if (icon == null) {
-			icon = DEFAULT_ICON;
+			if (bookmarkManager.isDefinedType(type)) {
+				// This implies the client defined a type, but did not pass a valid icon.  In this
+				// case we will show a special icon.
+				icon = DEFAULT_ICON;
+			}
 		}
 
 		Color color = bmt.getMarkerColor();
@@ -90,8 +94,23 @@ public class BookmarkNavigator {
 			color = DEFAULT_COLOR;
 		}
 
-		markerSet = markerService.createPointMarker(type + " Bookmarks", type + " Bookmarks",
-			bookmarkMgr.getProgram(), priority, true, true, false, color, icon);
+		//
+		// Be default, bookmarks appear with an icon on the left side of the Listing.  If there is
+		// no icon, then skip the icon and instead add a color marker on the right side of the 
+		// Listing so the user can see the bookmark.   As long as clients call BookmarkManager's 
+		// defineType() method with a valid icon, then we will show the icon, which is the expected
+		// behavior.
+		//
+		String markerName = type + " Bookmarks";
+		if (icon != null) {
+			markerSet = markerService.createPointMarker(markerName, markerName,
+				bookmarkMgr.getProgram(), priority, true, true, false, color, icon);
+		}
+		else {
+			markerSet =
+				markerService.createAreaMarker(markerName, markerName, bookmarkMgr.getProgram(),
+					priority, false, true, false, color);
+		}
 
 		markerSet.setMarkerDescriptor(new MarkerDescriptor() {
 
diff --git a/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkPlugin.java b/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkPlugin.java
index 53495d4cc8..8484023cfa 100644
--- a/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkPlugin.java
+++ b/Ghidra/Features/Base/src/main/java/ghidra/app/plugin/core/bookmark/BookmarkPlugin.java
@@ -306,12 +306,6 @@ public class BookmarkPlugin extends ProgramPlugin implements PopupActionProvider
 		}
 
 		BookmarkManager bookmarkManager = currentProgram.getBookmarkManager();
-		if (!bookmarkManager.isDefinedType(typeString)) {
-			// This implies the bookmark was created by a plugin that is no longer available in
-			// the current tool.
-			return null;
-		}
-
 		nav = new BookmarkNavigator(markerService, bookmarkManager, type);
 		bookmarkNavigators.put(typeString, nav);
 		return nav;