diff --git a/.idea/runConfigurations/CLion_2020_1.xml b/.idea/runConfigurations/CLion_2020_1.xml
index db6fb51..783aa27 100644
--- a/.idea/runConfigurations/CLion_2020_1.xml
+++ b/.idea/runConfigurations/CLion_2020_1.xml
@@ -1,7 +1,7 @@
 <component name="ProjectRunConfigurationManager">
   <configuration default="false" name="CLion 2020.1" type="#org.jetbrains.idea.devkit.run.PluginConfigurationType">
     <module name="CLionArduinoPlugin" />
-    <option name="VM_PARAMETERS" value="-Xmx2048m -Xms512m -ea -Didea.ProcessCanceledException=disabled" />
+    <option name="VM_PARAMETERS" value="-Xmx2048m -Xms512m -ea -Didea.is.internal=true -Didea.platform.prefix=CLion -XX:+UnlockDiagnosticVMOptions -XX:HeapDumpPath=$USER_HOME$/JetBrains/heapdump" />
     <option name="PROGRAM_PARAMETERS" value="" />
     <alternative-path path="CLion CL-201.8743.17" alternative-path-enabled="true" />
     <predefined_log_file enabled="true" id="idea.log" />
diff --git a/VERSION.md b/VERSION.md
index f90ee12..3eb6f1c 100644
--- a/VERSION.md
+++ b/VERSION.md
@@ -5,7 +5,7 @@
 ### Version History
 - [CLionArduinoPlugin Version Notes](#clionarduinoplugin-version-notes)
   - [TO DO](#to-do)
-  - [1.5.20 Next](#1520-next)
+  - [1.5.24 Next](#1524-next)
   - [1.5.11](#1511)
   - [1.5.9](#159)
   - [1.5.7](#157)
@@ -52,8 +52,10 @@
   * Add: inspection to check that `CMakeLists.txt` is out of sync, especially if missing the
     toolchain file.
 
-### 1.5.20 Next
+### 1.5.24 Next
 
+* Fix: disable diff buttons if the toolchain file is not `ArduinoToolchain.cmake` so that other
+  toolchain files will not be erroneously compared to bundled version.
 * Fix: add second diff button for toolchain diff viewing `Platform/Arduino.cmake`
 * Fix: allow directories to be selected for toolchain file path.
 * Fix: if a directory is selected add `ArduinoToolchain.cmake` file name automatically.
diff --git a/resources/META-INF/plugin.xml b/resources/META-INF/plugin.xml
index aa11cc8..467a918 100644
--- a/resources/META-INF/plugin.xml
+++ b/resources/META-INF/plugin.xml
@@ -1,10 +1,10 @@
 <?xml version="1.0" encoding="UTF-8"?>
-<idea-plugin>
+<idea-plugin url="http://github.com/vsch/CLionArduinoPlugin" require-restart="true">
     <id>com.vladsch.clionarduinoplugin</id>
     <name>Arduino Support</name>
-    <vendor email="" url="https://github.com/vsch/CLionArduinoPlugin">Vladimir Schneider</vendor>
+    <vendor email="vladimir.schneider@gmail.com" url="https://github.com/vsch">Vladimir Schneider</vendor>
 
-    <version>1.5.19</version>
+    <version>1.5.25</version>
     <!-- please see https://confluence.jetbrains.com/display/IDEADEV/Plugin+Compatibility+with+IntelliJ+Platform+Products
          on how to target different products -->
     <depends>com.intellij.modules.clion</depends>
diff --git a/resources/com/vladsch/clionarduinoplugin/localization/strings.properties b/resources/com/vladsch/clionarduinoplugin/localization/strings.properties
index 16aa666..35f4df3 100644
--- a/resources/com/vladsch/clionarduinoplugin/localization/strings.properties
+++ b/resources/com/vladsch/clionarduinoplugin/localization/strings.properties
@@ -67,6 +67,7 @@ settings.eol.crlf=CR/LF (\\r\\n : 0x0D 0x0A)
 settings.eol.lf=LF (\\n : 0x0A)
 settings.eol.none=None
 settings.file-templates.message=Path is a file
+settings.file-toolchain-txt.message=Toolchain file is not derived from the bundled version. Viewing difference is not applicable.
 settings.file-toolchain.message=Path is a file
 settings.invalid-boards-txt.message=Selected boards.txt file appears to be invalid. No boards are defined in it.
 settings.invalid-programmers-txt.message=Selected programmers.txt file appears to be invalid. No programmers are defined in it.
@@ -140,7 +141,9 @@ settings.toolchain-txt-create-failed.title=Create Toolchain Dir Failed
 settings.toolchain-txt-create-success.label=<html><body>Toolchain directory was successfully created<br>and populated with bundled toolchain files.<br><br>Path: {0}</body></html>
 settings.toolchain-txt-create-success.title=Toolchain Directory Created
 settings.toolchain-txt-create.label=Create From Bundled
+settings.toolchain-txt-diff.label=ArduinoToolchain Difference
 settings.toolchain-txt-diff.title=Show difference between bundled ArduinoToolchain.cmake and selected toolchain file
+settings.toolchain-txt-diff2.label=Platform/Arduino Difference
 settings.toolchain-txt-diff2.title=Show difference between bundled Platform/Arduino.cmake and selected toolchain file
 settings.toolchain-txt-file-directory.title=Select Path for Toolchain Directory
 settings.toolchain-txt-path.label=&CMake Toolchain File:
diff --git a/src/com/vladsch/clionarduinoplugin/components/ArduinoApplicationComponent.java b/src/com/vladsch/clionarduinoplugin/components/ArduinoApplicationComponent.java
index a06bcf4..b4eecb1 100644
--- a/src/com/vladsch/clionarduinoplugin/components/ArduinoApplicationComponent.java
+++ b/src/com/vladsch/clionarduinoplugin/components/ArduinoApplicationComponent.java
@@ -16,17 +16,12 @@ public ArduinoApplicationComponent() {
                     FileTypeManager.getInstance().associateExtension(cpp, Strings.INO_EXT);
                     FileTypeManager.getInstance().associateExtension(cpp, Strings.PDE_EXT);
                 }));
-        
-        Disposer.register(SerialPortManager.getInstance(), this);
     }
 
     public void dispose() {
-        ApplicationManager.getApplication().invokeLater(() ->
-                ApplicationManager.getApplication().runWriteAction(() -> {
-                    FileType cpp = FileTypeManager.getInstance().getFileTypeByExtension(Strings.CPP_EXT);
-                    FileTypeManager.getInstance().removeAssociatedExtension(cpp, Strings.INO_EXT);
-                    FileTypeManager.getInstance().removeAssociatedExtension(cpp, Strings.PDE_EXT);
-                }));
+        FileType cpp = FileTypeManager.getInstance().getFileTypeByExtension(Strings.CPP_EXT);
+        FileTypeManager.getInstance().removeAssociatedExtension(cpp, Strings.INO_EXT);
+        FileTypeManager.getInstance().removeAssociatedExtension(cpp, Strings.PDE_EXT);
     }
 
     static public ArduinoApplicationComponent getInstance() {
diff --git a/src/com/vladsch/clionarduinoplugin/serial/SerialProjectComponent.java b/src/com/vladsch/clionarduinoplugin/serial/SerialProjectComponent.java
index f8d1243..25a1849 100644
--- a/src/com/vladsch/clionarduinoplugin/serial/SerialProjectComponent.java
+++ b/src/com/vladsch/clionarduinoplugin/serial/SerialProjectComponent.java
@@ -89,7 +89,7 @@ public void dispose() {
             mySerialMonitorPanel = null;
             myApplicationComponent = null;
 
-            disconnectPort();
+            myPortManager.removeProjectComponent(this);
             myPortManager = null;
 
             myListeners.clear();
@@ -98,9 +98,6 @@ public void dispose() {
                 myBuildMonitor.projectClosed();
                 myBuildMonitor = null;
             }
-
-            SerialPortManager portManager = SerialPortManager.getInstance();
-            portManager.removeProjectComponent(this);
         }
     }
 
diff --git a/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.form b/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.form
index 66915d6..0a7e6f7 100644
--- a/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.form
+++ b/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.form
@@ -2,7 +2,7 @@
 <form xmlns="http://www.intellij.com/uidesigner/form/" version="1" bind-to-class="com.vladsch.clionarduinoplugin.settings.ApplicationSettingsForm">
   <grid id="27dc6" binding="myMainPanel" layout-manager="BorderLayout" hgap="0" vgap="0">
     <constraints>
-      <xy x="20" y="20" width="672" height="404"/>
+      <xy x="20" y="20" width="810" height="404"/>
     </constraints>
     <properties/>
     <border type="none"/>
@@ -288,7 +288,7 @@
                       <grid row="0" column="0" row-span="1" col-span="1" vsize-policy="0" hsize-policy="3" anchor="8" fill="0" indent="0" use-parent-layout="false"/>
                     </constraints>
                     <properties>
-                      <text resource-bundle="com/vladsch/clionarduinoplugin/localization/strings" key="settings.boards-txt-diff.label"/>
+                      <text resource-bundle="com/vladsch/clionarduinoplugin/localization/strings" key="settings.toolchain-txt-diff.label"/>
                       <toolTipText resource-bundle="com/vladsch/clionarduinoplugin/localization/strings" key="settings.toolchain-txt-diff.title"/>
                     </properties>
                   </component>
@@ -297,7 +297,7 @@
                       <grid row="0" column="1" row-span="1" col-span="1" vsize-policy="0" hsize-policy="3" anchor="8" fill="0" indent="0" use-parent-layout="false"/>
                     </constraints>
                     <properties>
-                      <text resource-bundle="com/vladsch/clionarduinoplugin/localization/strings" key="settings.boards-txt-diff.label"/>
+                      <text resource-bundle="com/vladsch/clionarduinoplugin/localization/strings" key="settings.toolchain-txt-diff2.label"/>
                       <toolTipText resource-bundle="com/vladsch/clionarduinoplugin/localization/strings" key="settings.toolchain-txt-diff2.title"/>
                     </properties>
                   </component>
diff --git a/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.java b/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.java
index 6bae6e2..2a2310d 100644
--- a/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.java
+++ b/src/com/vladsch/clionarduinoplugin/settings/ApplicationSettingsForm.java
@@ -572,42 +572,46 @@ void updateOptions(boolean onSet) {
                 } else {
                     // try to open and read the file
                     File file = new File(toolchainTxtPathText);
-                    if (!file.exists() || file.isDirectory()) {
-                        if (file.isDirectory()) {
-                            // add file name automatically 
-                            Path toolchainPath = Path.of(toolchainTxtPathText, "ArduinoToolchain.cmake");
-                            toolchainTxtPathText = toolchainPath.toString();
-                            file = toolchainPath.toFile();
-                            String finalToolchainTxtPathText = toolchainTxtPathText;
-                            ApplicationManager.getApplication().invokeLater(() -> {
-                                myToolchainTxtPath.setText(finalToolchainTxtPathText);
-                            });
-                            //error = "<html><body><span style='color: red'>" + Bundle.message("settings.not-exists-toolchain-directory.message") + "</span></body></html>";
-                        }
+                    if (file.getName().equals("ArduinoToolchain.cmake")) {
+                        if (!file.exists() || file.isDirectory()) {
+                            if (file.isDirectory()) {
+                                // add file name automatically 
+                                Path toolchainPath = Path.of(toolchainTxtPathText, "ArduinoToolchain.cmake");
+                                toolchainTxtPathText = toolchainPath.toString();
+                                file = toolchainPath.toFile();
+                                String finalToolchainTxtPathText = toolchainTxtPathText;
+                                ApplicationManager.getApplication().invokeLater(() -> {
+                                    myToolchainTxtPath.setText(finalToolchainTxtPathText);
+                                });
+                                //error = "<html><body><span style='color: red'>" + Bundle.message("settings.not-exists-toolchain-directory.message") + "</span></body></html>";
+                            }
 
-                        String parentPath = file.getParent();
+                            String parentPath = file.getParent();
 
-                        while (!parentPath.isEmpty()) {
-                            File parent = new File(parentPath);
-                            if (parent.exists()) {
-                                canCreate = parent.isDirectory() && parent.canRead() && parent.canWrite();
-                                break;
-                            }
-                            int pos = parentPath.lastIndexOf(File.separator);
-                            if (pos <= 0) break;
+                            while (!parentPath.isEmpty()) {
+                                File parent = new File(parentPath);
+                                if (parent.exists()) {
+                                    canCreate = parent.isDirectory() && parent.canRead() && parent.canWrite();
+                                    break;
+                                }
+                                int pos = parentPath.lastIndexOf(File.separator);
+                                if (pos <= 0) break;
 
-                            parentPath = parentPath.substring(0, pos);
-                        }
-                        if (!canCreate) {
-                            error = "<html><body><span style='color: red'>" + Bundle.message("settings.not-exists-toolchain-rw.message") + "</span></body></html>";
+                                parentPath = parentPath.substring(0, pos);
+                            }
+                            if (!canCreate) {
+                                error = "<html><body><span style='color: red'>" + Bundle.message("settings.not-exists-toolchain-rw.message") + "</span></body></html>";
+                            } else {
+                                error = "<html><body><span style='color: red'>" + Bundle.message("settings.not-exists-toolchain.message") + "</span></body></html>";
+                            }
+                        } else if (file.isDirectory()) {
+                            error = "<html><body><span style='color: red'>" + Bundle.message("settings.file-toolchain.message") + "</span></body></html>";
                         } else {
-                            error = "<html><body><span style='color: red'>" + Bundle.message("settings.not-exists-toolchain.message") + "</span></body></html>";
+                            // not necessarily our bundled toolchain
+                            canShowDiff = true;
                         }
-                    } else if (file.isDirectory()) {
-                        error = "<html><body><span style='color: red'>" + Bundle.message("settings.file-toolchain.message") + "</span></body></html>";
                     } else {
-                        // not necessarily our bundled toolchain
-                        canShowDiff = true;
+                        error = "<html><body><span style='color: red'>" + Bundle.message("settings.file-toolchain-txt.message") + "</span></body></html>";
                     }
                 }
 
diff --git a/update-sandboxes.sh b/update-sandboxes.sh
index 7043024..bf53f0c 100755
--- a/update-sandboxes.sh
+++ b/update-sandboxes.sh
@@ -16,6 +16,18 @@ IDE_LIST_NEW_LOCATION=(
     "CLion2023.1"
     "CLion2023.2"
     "CLion2023.3"
+    "CLion2020-1"
+    "CLion2020-2"
+    "CLion2020-3"
+    "CLion2021-1"
+    "CLion2021-2"
+    "CLion2021-3"
+    "CLion2022-1"
+    "CLion2022-2"
+    "CLion2022-3"
+    "CLion2023-1"
+    "CLion2023-2"
+    "CLion2023-3"
     "IdeaIC2020-1-EAP"
     "IdeaIC2020-2-EAP"
     "IdeaIC2020-3-EAP"
@@ -88,6 +100,8 @@ function Upd() {
 # Upd "CLion2020-2" "plugins-sandbox"
 # Upd "CLion2020-3" "plugins-sandbox"
 Upd "CLion2021-2" "plugins-sandbox"
+Upd "CLion2021-3" "plugins-sandbox"
+# Upd "CLion2023-1" "plugins-sandbox"
 
 # for plugin debugging in intellij-community under debugging
 # UpdRaw "/Users/vlad/src/intellij-community/system/plugins-sandbox/plugins"
