commit 7895f091aab89dfa794b86d229850b930ed0bd2e
Author: Emmanuel Lepage Vallee <elv1313@gmail.com>
Date:   Wed May 28 00:46:17 2014 -0400

    Fix flawed tag deletion logic (FS#1268)

    The sticky use case was dubious as if there is no fallback tag,
    the process abort early. Then, the new selected tag doesn't have
    to be random, as the fallback is always a better choice.

    Finally, this fix an issue where clients with multiple tags were
    simply not supported. It is a very useful feature if used with
    some implementation of tag forking. The current implementation
    caused the client to be untagged from all other tags. As the
    fallback tag is designed to avoid a client having no tags, it is
    not needed (nor wanted) in that case.

diff --git a/lib/awful/tag.lua.in b/lib/awful/tag.lua.in
index 58b0a34..40a5bc0 100644
--- a/lib/awful/tag.lua.in
+++ b/lib/awful/tag.lua.in
@@ -139,14 +139,19 @@ function tag.delete(target_tag, fallback_tag)
     local clients = target_tag:clients()
     if ( #clients > 0 and ntags <= 1 ) or fallback_tag == nil then return end

+    -- Keep a possible candidate in case no selected tag is available
+    -- it is very rare, but possible if a client have been automatically tagged
+    local candidate = fallback_tag
+
     -- Move the clients we can off of this tag.
     for _, c in pairs(clients) do
+        local current_tags = c:tags()

-        -- If a client has only this tag, or stickied clients with
-        -- nowhere to go, abort.
-        if (not c.sticky and #c:tags() == 1) or
-                                    (c.sticky and fallback_tag == nil) then
-            return
+        -- Do not use a "random" tags as fallback if the client already have some
+        if #current_tags > 1 then
+            current_tags[util.table.hasitem(current_tags,target_tag)] = nil
+            c:tags(current_tags)
+            candidate = current_tags[1]
         else
             c:tags({fallback_tag})
         end
@@ -160,7 +165,8 @@ function tag.delete(target_tag, fallback_tag)
     if tag.selected(target_scr) == nil and ntags > 0 then
         tag.history.restore(nil, 1)
         if tag.selected(target_scr) == nil then
-            tag.gettags(target_scr)[1].selected = true
+            local next_tag = candidate or tag.gettags(target_scr)[1]
+            next_tag.selected = true
         end
     end