Wicket: concurrent Ajax requests limited to one?

Situation

In my Wicket application, I have a page which contains two tags. Each time a tab is selected, its content is fetched via Ajax so that every time you switch to a different tab its content it loaded fresh from the server.

On one of the tabs I have an input field which has an onblur event which saves the contents of the field via Ajax.

Problem

If the focus is on the input field and I click to a blank area of the page, the Ajax request it fired and the data saved.

If, instead of clicking on a blank area of the page, I click on the other tab, the Ajax request to save the input field is fired but not the Ajax request to switch tabs.

Is the number of concurrent Ajax requests limited in Wicket to one?