Queue login multiple queues selection

Queue login works great when a single queue is selected in the 'Accept' pop-up at FOP2 login time. But if multiple queues are selected (holding the control key down), only one or two of the selected queues will be joined. From a network trace, it looks as though all selected queues are requested:

<msg data="2516^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|2516^LOCALHOST" />
<msg data="2517^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|2517^LOCALHOST" />
<msg data="2518^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|2518^LOCALHOST" />
<msg data="2519^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|2519^LOCALHOST" />
<msg data="2574^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|2574^LOCALHOST" />
<msg data="3501^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|3501^LOCALHOST" />
<msg data="3502^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|3502^LOCALHOST" />
<msg data="3503^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|3503^LOCALHOST" />
<msg data="3504^LOCALHOST|queueadd|91-91|67704feaa6e08cce07755a2afa926131" />
<msg data="91|queueloginqueues|3504^LOCALHOST" />

Browser is IE10 or Firefox 34.0.5, Asterisk is Elastix with FreePBX 2.9.0.7 (FOP2 2.28).

Any ideas greatly appreciated.

As a workaround, is there a way to trigger the 'Accept' pop-up once logged in to FOP2 (i.e. to add oneself to additional queues)?

Thanks!