diff --git a/common/content/ui.js b/common/content/ui.js
index d01f2a2c..a23e5de7 100644
--- a/common/content/ui.js
+++ b/common/content/ui.js
@@ -1298,8 +1298,15 @@ function CommandLine() //{{{
                 // user pressed ENTER to carry out a command
                 // user pressing ESCAPE is handled in the global onEscape
                 //   FIXME: <Esc> should trigger "cancel" event
+                //   FIXME: This should not be waiting, some kind of callback mechanism on completion would be better.
                 if (events.isAcceptKey(key))
                 {
+                    while (completions.context.incomplete)
+                    {
+                        liberator.threadYield(true);
+                        command = this.command;
+                    }
+
                     let mode = currentExtendedMode; // save it here, as modes.pop() resets it
                     keepCommand = true;
                     currentExtendedMode = null; // Don't let modes.pop trigger "cancel"