diff --git a/src/terminal_ui.cc b/src/terminal_ui.cc
index 2ff84312..a067809f 100644
--- a/src/terminal_ui.cc
+++ b/src/terminal_ui.cc
@@ -228,6 +228,9 @@ void TerminalUI::Screen::output(bool force)
     if (lines.empty())
         return;
 
+    if (force)
+        hashes.clear();
+
     // iTerm2 "begin synchronised update" sequence
     printf("\033P=1s\033\\");