diff --git a/app/src/processing/app/Base.java b/app/src/processing/app/Base.java
index 49a8625e5..839eb6889 100644
--- a/app/src/processing/app/Base.java
+++ b/app/src/processing/app/Base.java
@@ -1155,6 +1155,7 @@ public void handleOpenPrompt() {
       // use the front-most window frame for placing file dialog
       FileDialog openDialog =
         new FileDialog(activeEditor, prompt, FileDialog.LOAD);
+        openDialog.setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
 
       // Only show .pde files as eligible bachelors
       openDialog.setFilenameFilter((dir, name) -> {
diff --git a/app/src/processing/app/Messages.kt b/app/src/processing/app/Messages.kt
index 9b4ac7cd0..76e936895 100644
--- a/app/src/processing/app/Messages.kt
+++ b/app/src/processing/app/Messages.kt
@@ -48,6 +48,19 @@ import javax.swing.UIManager
 
 class Messages {
     companion object {
+
+        /**
+         * Shows a modal dialog that only blocks its parent window,
+         * not all windows in the application.
+         */
+        private fun showModalDialog(message: Any, title: String, messageType: Int) {
+            val activeWindow = java.awt.KeyboardFocusManager
+                .getCurrentKeyboardFocusManager().activeWindow
+            val pane = JOptionPane(message, messageType)
+            val dialog = pane.createDialog(activeWindow, title)
+            dialog.modalityType = java.awt.Dialog.ModalityType.DOCUMENT_MODAL
+            dialog.isVisible = true
+        }
         /**
          * "No cookie for you" type messages. Nothing fatal or all that
          * much of a bummer, but something to notify the user about.
@@ -57,10 +70,7 @@ class Messages {
             if (Base.isCommandLine()) {
                 println("$title: $message")
             } else {
-                JOptionPane.showMessageDialog(
-                    Frame(), message, title,
-                    JOptionPane.INFORMATION_MESSAGE
-                )
+                showModalDialog(message, title, JOptionPane.INFORMATION_MESSAGE)
             }
         }
 
@@ -77,10 +87,7 @@ class Messages {
             if (Base.isCommandLine()) {
                 println("$title: $message")
             } else {
-                JOptionPane.showMessageDialog(
-                    Frame(), message, title,
-                    JOptionPane.WARNING_MESSAGE
-                )
+                showModalDialog(message, title, JOptionPane.WARNING_MESSAGE)
             }
             e?.printStackTrace()
         }
@@ -101,11 +108,7 @@ class Messages {
                 println("$title: $primary\n$secondary")
             } else {
                 EventQueue.invokeLater {
-                    JOptionPane.showMessageDialog(
-                        JFrame(),
-                        Toolkit.formatMessage(primary, secondary),
-                        title, JOptionPane.WARNING_MESSAGE
-                    )
+                    showModalDialog(Toolkit.formatMessage(primary, secondary), title, JOptionPane.WARNING_MESSAGE)
                 }
             }
             e?.printStackTrace()
@@ -122,10 +125,7 @@ class Messages {
             if (Base.isCommandLine()) {
                 System.err.println("$title: $message")
             } else {
-                JOptionPane.showMessageDialog(
-                    Frame(), message, title,
-                    JOptionPane.ERROR_MESSAGE
-                )
+                showModalDialog(message, title, JOptionPane.ERROR_MESSAGE)
             }
             e?.printStackTrace()
             System.exit(1)
@@ -151,9 +151,7 @@ class Messages {
                 val sw = StringWriter()
                 t!!.printStackTrace(PrintWriter(sw))
 
-                JOptionPane.showMessageDialog(
-                    Frame(),  // first <br/> clears to the next line
-                    // second <br/> is a shorter height blank space before the trace
+                showModalDialog(
                     Toolkit.formatMessage("$message<br/><tt><br/>$sw</tt>"),
                     title,
                     if (fatal) JOptionPane.ERROR_MESSAGE else JOptionPane.WARNING_MESSAGE
diff --git a/app/src/processing/app/Sketch.java b/app/src/processing/app/Sketch.java
index 8bb50352b..124adac86 100644
--- a/app/src/processing/app/Sketch.java
+++ b/app/src/processing/app/Sketch.java
@@ -34,6 +34,7 @@
 import java.awt.Container;
 import java.awt.EventQueue;
 import java.awt.FileDialog;
+import java.awt.Dialog;
 import java.awt.event.ActionListener;
 import java.awt.event.KeyAdapter;
 import java.awt.event.KeyEvent;
@@ -866,6 +867,7 @@ public boolean saveAs() throws IOException {
     if (useNative) {
       // get new name for folder
       FileDialog fd = new FileDialog(editor, PROMPT, FileDialog.SAVE);
+      fd.setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
       if (isReadOnly() || isUntitled()) {
         // default to the sketchbook folder
         fd.setDirectory(Preferences.getSketchbookPath());
@@ -1387,6 +1389,7 @@ public void handleAddFile() {
     String prompt = Language.text("file");
     //FileDialog fd = new FileDialog(new Frame(), prompt, FileDialog.LOAD);
     FileDialog fd = new FileDialog(editor, prompt, FileDialog.LOAD);
+    fd.setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
     fd.setVisible(true);
 
     String directory = fd.getDirectory();
diff --git a/core/src/processing/awt/ShimAWT.java b/core/src/processing/awt/ShimAWT.java
index 304b8dd2a..5c6c061b7 100644
--- a/core/src/processing/awt/ShimAWT.java
+++ b/core/src/processing/awt/ShimAWT.java
@@ -818,6 +818,7 @@ static public void selectImpl(final String prompt,
 
         if (PApplet.useNativeSelect) {
             FileDialog dialog = new FileDialog(parentFrame, prompt, mode);
+            dialog.setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
             if (defaultSelection != null) {
                 dialog.setDirectory(defaultSelection.getParent());
                 dialog.setFile(defaultSelection.getName());
@@ -910,6 +911,7 @@ static public void selectFolderImpl(final String prompt,
     if (PApplet.platform == PConstants.MACOS && PApplet.useNativeSelect) {
       FileDialog fileDialog =
         new FileDialog(parentFrame, prompt, FileDialog.LOAD);
+      fileDialog.setModalityType(Dialog.ModalityType.DOCUMENT_MODAL);
       if (defaultSelection != null) {
         fileDialog.setDirectory(defaultSelection.getAbsolutePath());
       }