[bug] urxvt with tabbed extension disable input

[Xuefer]

without tabbed extension, when i click my mouse on window decoration
(border), i can input in urxvt
with tabbed extension loaded, when i click my mouse on window
decoration (border), or with x-style mouse focusing on it, i cannot
input in urxvt until i click on the urxvt text display area.

focus on window decoration includes:
 * click mouse on window decoration
 * move mouse over window decoration with x-style mouse
 * in fvwm, switch to urxvt with alt+tab and the mouse is on window decoration