Steps to reproduce

When clicking a link to download a file, if the target is the same page (target="_self"), a desktop cleanup (rmDesktop) is triggered, which stops the client engine.

Root cause

See attached example
Button send a request and display an alert (to test the activity of the client engine)
the "with blank target" link open the download in a new tab
the "with selft target" link open the download in the current page.

Workaround

1. target='_blank'

2. download attribute

<zk xmlns:c="client/attribute">
<a href="report.xls" c:download="" target='_self'>download</a>
</zk>

ref: https://developer.mozilla.org/en-US/docs/Web/HTML/Element/a#attr-download

3. hidden iframe

<a target="dltarget" href="http://localhost:8080/tabbox_problem/test.zip">Link Link liiiiinkk bling bling</a>
<button id="btn" label="Click me first, then link and again me, second click will not fire messagebox" />
<iframe style="display:none" name="dltarget"/>