Support copying in the alt buffer

src/InputHandler.ts

@@ -1130,6 +1130,8 @@ export class InputHandler implements IInputHandler {
             this._terminal.scrollBottom = this._terminal.normal.scrollBottom;
             this._terminal.tabs = this._terminal.normal.tabs;
             this._terminal.normal = null;
+            // Ensure the selection manager has the correct buffer
+            this._terminal.selectionManager.setBuffer(this._terminal.lines);
             // if (params === 1049) {
             //   this.x = this.savedX;
             //   this.y = this.savedY;

src/SelectionManager.ts

@@ -136,6 +136,15 @@ export class SelectionManager extends EventEmitter {
     this._rowContainer.addEventListener('mousedown', this._mouseDownListener);
   }
 
+  /**
+   * Sets the active buffer, this should be called when the alt buffer is
+   * switched in or out.
+   * @param buffer The active buffer.
+   */
+  public setBuffer(buffer: CircularList<any>): void {
+    this._buffer = buffer;
+  }
+
   /**
    * Gets the text currently selected.
    */

src/xterm.js

@@ -251,6 +251,10 @@ function Terminal(options) {
   while (i--) {
     this.lines.push(this.blankLine());
   }
+  // Ensure the selection manager has the correct buffer
+  if (this.selectionManager) {
+    this.selectionManager.setBuffer(this.lines);
+  }
 
   this.tabs;
   this.setupStops();