diff --git a/lib/program.js b/lib/program.js
index 6c26821..afefb7d 100644
--- a/lib/program.js
+++ b/lib/program.js
@@ -1495,9 +1495,14 @@ Program.prototype._write = function(text) {
 // Example: `DCS tmux; ESC Pt ST`
 // Real: `DCS tmux; ESC Pt ESC \`
 Program.prototype._twrite = function(data) {
-  if (this.tmux) data = '\x1bPtmux;\x1b' + data + '\x1b\\';
-  // Should work but tmux doesn't implement ST correctly:
-  // if (this.tmux) data = '\x1bPtmux;\x1b' + data + '\x07';
+  if (this.tmux) {
+    data = '\x1bPtmux;\x1b' + data + '\x1b\\';
+    // Should work but tmux doesn't implement ST correctly:
+    // data = '\x1bPtmux;\x1b' + data + '\x07';
+    // NOTE: Flushing the buffer is required in some cases.
+    this.flush();
+    return this.output.write(data);
+  }
   return this._write(data);
 };