diff --git a/common/content/ui.js b/common/content/ui.js
index e069478f..f67f89a5 100644
--- a/common/content/ui.js
+++ b/common/content/ui.js
@@ -384,37 +384,41 @@ function CommandLine() //{{{
                 if (idx == -2)
                     list = list.slice().reverse();
                 let n = 0;
-                for (let [,context] in Iterator(list))
+                try
                 {
-                    function done() !(idx >= n + context.items.length || idx == -2 && !context.items.length);
-                    while (context.incomplete && !done())
+                    this.waiting = true;
+                    for (let [,context] in Iterator(list))
                     {
-                        // threadYield(true, true) would be better, but it does not return on my
-                        // machine until all awesomebar completions were reported, making
-                        // :open foo<tab> nearly unusable, if the first 2 foo-completions would
-                        // be there fast, but it takes up to 20 sec to find more foo-completions
-                        //
-                        // The strange thing is, I tested the 2009-01-07 nightly at work in Windows
-                        // and it seemed to work perfectly there. Will have to see if it's a
-                        // hardware (dual core there, vs. P4 at home) issue or an OS issue.
-                        //
-                        // While I *really* prefer this solution over my hack
-                        // when it works, we can't have a nearly-defect :open
-                        // prompt when releasing vimp 2.0, even not just on certain
-                        // computers, as :open is probably the most often used ex-command
-                        // in vimperator
-                        //
-                        // liberator.threadYield(false, true); is just a temporary measure as
-                        // it has other problems (hitting tab often in a row), until we find the
-                        // source of the problem (which we hopefully do, as I really don't want to
-                        // have to revert to my hack when better solutions exist)
-                        liberator.dump("before yielding");
-                        liberator.threadYield(false, true);
-                        liberator.dump("after yielding");
+                        function done() !(idx >= n + context.items.length || idx == -2 && !context.items.length);
+                        while (context.incomplete && !done())
+                            // threadYield(true, true) would be better, but it does not return on my
+                            // machine until all awesomebar completions were reported, making
+                            // :open foo<tab> nearly unusable, if the first 2 foo-completions would
+                            // be there fast, but it takes up to 20 sec to find more foo-completions
+                            //
+                            // The strange thing is, I tested the 2009-01-07 nightly at work in Windows
+                            // and it seemed to work perfectly there. Will have to see if it's a
+                            // hardware (dual core there, vs. P4 at home) issue or an OS issue.
+                            //
+                            // While I *really* prefer this solution over my hack
+                            // when it works, we can't have a nearly-defect :open
+                            // prompt when releasing vimp 2.0, even not just on certain
+                            // computers, as :open is probably the most often used ex-command
+                            // in vimperator
+                            //
+                            // liberator.threadYield(false, true); is just a temporary measure as
+                            // it has other problems (hitting tab often in a row), until we find the
+                            // source of the problem (which we hopefully do, as I really don't want to
+                            // have to revert to my hack when better solutions exist)
+                            liberator.threadYield(false, true);
+                        if (done())
+                            break;
+                        n += context.items.length;
                     }
-                    if (done())
-                        break;
-                    n += context.items.length;
+                }
+                finally
+                {
+                    this.waiting = false;
                 }
 
                 // See previous FIXME. This will break if new items in
@@ -429,6 +433,8 @@ function CommandLine() //{{{
             this.itemList.selectItem(idx);
         },
 
+        ntab: 0,
+
         tab: function tab(reverse)
         {
             autocompleteTimer.flush();
@@ -436,34 +442,41 @@ function CommandLine() //{{{
             if (this.context.waitingForTab || this.wildIndex == -1)
                 this.complete(true, true);
 
-            switch (this.wildtype.replace(/.*:/, ""))
+            this.ntab++;
+            if (this.waiting)
+                return;
+
+            while (this.ntab--)
             {
-                case "":
-                    this.select(0);
-                    break;
-                case "longest":
-                    if (this.items.length > 1)
-                    {
-                        if (this.substring && this.substring != this.completion)
-                            this.completion = this.substring;
+                switch (this.wildtype.replace(/.*:/, ""))
+                {
+                    case "":
+                        this.select(0);
                         break;
-                    }
-                    // Fallthrough
-                case "full":
-                    this.select(reverse ? this.UP : this.DOWN)
-                    break;
+                    case "longest":
+                        if (this.items.length > 1)
+                        {
+                            if (this.substring && this.substring != this.completion)
+                                this.completion = this.substring;
+                            break;
+                        }
+                        // Fallthrough
+                    case "full":
+                        this.select(reverse ? this.UP : this.DOWN)
+                        break;
+                }
+
+                if (this.type.list)
+                    completionList.show();
+
+                this.wildIndex = Math.max(0, Math.min(this.wildtypes.length - 1, this.wildIndex + 1));
+                this.preview();
+
+                statusTimer.tell();
             }
 
             if (this.items.length == 0)
-                return void liberator.beep();
-
-            if (this.type.list)
-                completionList.show();
-
-            this.wildIndex = Math.max(0, Math.min(this.wildtypes.length - 1, this.wildIndex + 1));
-            this.preview();
-
-            statusTimer.tell();
+                liberator.beep();
         }
     }