diff --git a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfiguration.java b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfiguration.java
index 5f2a65b4874..7be7a1bdafb 100644
--- a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfiguration.java
+++ b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfiguration.java
@@ -18,6 +18,7 @@ import java.util.HashMap;
 import java.util.List;
 import java.util.Map;
 
+import org.eclipse.cdt.core.CCorePlugin;
 import org.eclipse.cdt.core.CommandLauncherManager;
 import org.eclipse.cdt.core.ConsoleOutputStream;
 import org.eclipse.cdt.core.ErrorParserManager;
@@ -26,6 +27,7 @@ import org.eclipse.cdt.core.build.CBuildConfiguration;
 import org.eclipse.cdt.core.build.ICBuildCommandLauncher;
 import org.eclipse.cdt.core.build.IToolChain;
 import org.eclipse.cdt.core.model.ICModelMarker;
+import org.eclipse.cdt.core.parser.IExtendedScannerInfo;
 import org.eclipse.cdt.core.resources.IConsole;
 import org.eclipse.cdt.meson.core.Activator;
 import org.eclipse.cdt.meson.core.IMesonConstants;
@@ -91,6 +93,10 @@ public class MesonBuildConfiguration extends CBuildConfiguration {
 		}
 	}
 
+	public IMesonToolChainFile getToolChainFile() {
+	    return toolChainFile;
+	}
+
 	private boolean isLocal() throws CoreException {
 		IToolChain toolchain = getToolChain();
 		return Platform.getOS().equals(toolchain.getProperty(IToolChain.ATTR_OS))
@@ -315,5 +321,4 @@ public class MesonBuildConfiguration extends CBuildConfiguration {
 	}
 	
 
-
 }
diff --git a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfigurationProvider.java b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfigurationProvider.java
index dbe4b455f4e..c321a73a8b0 100644
--- a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfigurationProvider.java
+++ b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonBuildConfigurationProvider.java
@@ -41,7 +41,7 @@ public class MesonBuildConfigurationProvider implements ICBuildConfigurationProv
 	}
 
 	@Override
-	public ICBuildConfiguration getCBuildConfiguration(IBuildConfiguration config, String name) throws CoreException {
+	public synchronized ICBuildConfiguration getCBuildConfiguration(IBuildConfiguration config, String name) throws CoreException {
 		if (config.getName().equals(IBuildConfiguration.DEFAULT_CONFIG_NAME)) {
 			IToolChain toolChain = null;
 
@@ -69,7 +69,19 @@ public class MesonBuildConfigurationProvider implements ICBuildConfigurationProv
 			// No valid combinations
 			return null;
 		}
-		return new MesonBuildConfiguration(config, name);
+		MesonBuildConfiguration mesonConfig = new MesonBuildConfiguration(config, name);
+		IMesonToolChainFile tcFile = mesonConfig.getToolChainFile();
+		IToolChain toolChain = mesonConfig.getToolChain();
+		if (toolChain == null || tcFile == null) {
+			// config not complete?
+			return null;
+		}
+		if (!toolChain.equals(tcFile.getToolChain())) {
+			// toolchain changed
+			return new MesonBuildConfiguration(config, name, tcFile.getToolChain(), tcFile,
+					mesonConfig.getLaunchMode());
+		}
+		return mesonConfig;
 	}
 
 	@Override
@@ -90,6 +102,7 @@ public class MesonBuildConfigurationProvider implements ICBuildConfigurationProv
 			Collection<IMesonToolChainFile> files = manager.getToolChainFilesMatching(properties);
 			if (!files.isEmpty()) {
 				file = files.iterator().next();
+				toolChain = file.getToolChain();
 			}
 		}
 
diff --git a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonToolChainManager.java b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonToolChainManager.java
index 73b6b5e275b..e7c7ade2670 100644
--- a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonToolChainManager.java
+++ b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/internal/meson/core/MesonToolChainManager.java
@@ -215,7 +215,7 @@ public class MesonToolChainManager implements IMesonToolChainManager {
 			SafeRunner.run(new ISafeRunnable() {
 				@Override
 				public void run() throws Exception {
-					listener.handleCMakeToolChainEvent(event);
+					listener.handleMesonToolChainEvent(event);
 				}
 
 				@Override
diff --git a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/meson/core/IMesonToolChainListener.java b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/meson/core/IMesonToolChainListener.java
index 6e1cda8e957..283d9449b2a 100644
--- a/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/meson/core/IMesonToolChainListener.java
+++ b/build/org.eclipse.cdt.meson.core/src/org/eclipse/cdt/meson/core/IMesonToolChainListener.java
@@ -14,6 +14,6 @@ package org.eclipse.cdt.meson.core;
  */
 public interface IMesonToolChainListener {
 
-	void handleCMakeToolChainEvent(MesonToolChainEvent event);
+	void handleMesonToolChainEvent(MesonToolChainEvent event);
 
 }
diff --git a/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/MesonPreferencePage.java b/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/MesonPreferencePage.java
index 487dc326e47..3d548fd7f82 100644
--- a/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/MesonPreferencePage.java
+++ b/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/MesonPreferencePage.java
@@ -104,11 +104,11 @@ public class MesonPreferencePage extends PreferencePage implements IWorkbenchPre
 				WizardDialog dialog = new WizardDialog(getShell(), wizard);
 				if (dialog.open() == Window.OK) {
 					IMesonToolChainFile file = wizard.getNewFile();
-					if (filesToRemove.containsKey(file.getPath())) {
-						filesToRemove.remove(file.getPath());
-					} else {
-						filesToAdd.put(file.getPath(), file);
+					IMesonToolChainFile oldFile = manager.getToolChainFile(file.getPath());
+					if (oldFile != null) {
+						filesToRemove.put(oldFile.getPath(), oldFile);
 					}
+					filesToAdd.put(file.getPath(), file);
 					updateTable();
 				}
 			}
@@ -166,27 +166,27 @@ public class MesonPreferencePage extends PreferencePage implements IWorkbenchPre
 			files.put(file.getPath(), file);
 		}
 
-		for (IMesonToolChainFile file : filesToAdd.values()) {
-			files.put(file.getPath(), file);
-		}
-
 		for (IMesonToolChainFile file : filesToRemove.values()) {
 			files.remove(file.getPath());
 		}
+		
+		for (IMesonToolChainFile file : filesToAdd.values()) {
+			files.put(file.getPath(), file);
+		}
 
 		return files;
 	}
 
 	@Override
 	public boolean performOk() {
-		for (IMesonToolChainFile file : filesToAdd.values()) {
-			manager.addToolChainFile(file);
-		}
-
 		for (IMesonToolChainFile file : filesToRemove.values()) {
 			manager.removeToolChainFile(file);
 		}
 
+		for (IMesonToolChainFile file : filesToAdd.values()) {
+			manager.addToolChainFile(file);
+		}
+		
 		filesToAdd.clear();
 		filesToRemove.clear();
 		
diff --git a/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/NewMesonToolChainFilePage.java b/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/NewMesonToolChainFilePage.java
index 4bcf5aabc1e..f7d3075c386 100644
--- a/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/NewMesonToolChainFilePage.java
+++ b/build/org.eclipse.cdt.meson.ui/src/org/eclipse/cdt/internal/meson/ui/NewMesonToolChainFilePage.java
@@ -113,6 +113,7 @@ public class NewMesonToolChainFilePage extends WizardPage {
 		IMesonToolChainFile file = manager.newToolChainFile(Paths.get(pathText.getText()));
 
 		IToolChain tc = toolchains[tcCombo.getSelectionIndex()];
+
 		file.setProperty(ICBuildConfiguration.TOOLCHAIN_TYPE, tc.getTypeId());
 		file.setProperty(ICBuildConfiguration.TOOLCHAIN_ID, tc.getId());