Middle mouse button pastes text only on linux: on other OSs it does nothing. Fixes #3266

app/src/processing/app/syntax/MyConfigurableCaret.java

@@ -0,0 +1,23 @@
+package processing.app.syntax;
+
+import org.fife.ui.rtextarea.ConfigurableCaret;
+import processing.app.helpers.OSUtils;
+
+import javax.swing.*;
+import java.awt.event.MouseEvent;
+
+public class MyConfigurableCaret extends ConfigurableCaret {
+
+  @Override
+  public void mouseClicked(MouseEvent e) {
+    if (e.isConsumed()) {
+      return;
+    }
+
+    if (!OSUtils.isLinux() && SwingUtilities.isMiddleMouseButton(e)) {
+      return;
+    }
+
+    super.mouseClicked(e);
+  }
+}

app/src/processing/app/syntax/SketchTextAreaUI.java

@@ -3,6 +3,7 @@ package processing.app.syntax;
 import org.fife.ui.rsyntaxtextarea.RSyntaxTextAreaUI;
 
 import javax.swing.*;
+import javax.swing.text.Caret;
 import javax.swing.text.EditorKit;
 import javax.swing.text.JTextComponent;
 
@@ -18,4 +19,11 @@ public class SketchTextAreaUI extends RSyntaxTextAreaUI {
   public EditorKit getEditorKit(JTextComponent tc) {
     return defaultKit;
   }
+
+  @Override
+  protected Caret createCaret() {
+    Caret caret = new MyConfigurableCaret();
+    caret.setBlinkRate(500);
+    return caret;
+  }
 }