Various fixes

- Add buffers being retained on full reset (CIS)
- Remove setup event, simplify
- Only have one trim listener active at once
- Disallow activate events if nothing changed (just in case)

src/Terminal.ts

@@ -292,7 +292,6 @@ export class Terminal extends EventEmitter implements ITerminal, IInputHandlingT
 
     // Create the terminal's buffers and set the current buffer
     this.buffers = new BufferSet(this);
-    this.emit('setup');
   }
 
   /**
@@ -2077,9 +2076,11 @@ export class Terminal extends EventEmitter implements ITerminal, IInputHandlingT
     this.options.cols = this.cols;
     const customKeyEventHandler = this.customKeyEventHandler;
     const inputHandler = this.inputHandler;
+    const buffers = this.buffers;
     this.setup();
     this.customKeyEventHandler = customKeyEventHandler;
     this.inputHandler = inputHandler;
+    this.buffers = buffers;
     this.refresh(0, this.rows - 1);
     this.viewport.syncScrollArea();
   }