A multiple-select box is wired up with Javascript to submit its form to an iframe on the same page when the user selection is changed. However, the Safari command-click behavior of loading form submissions in a new tab prevents Safari users from selecting multiple discontinuous entries in either <select> box. Instead of loading in the iframe, the form submission loads into a new tab. The bug appears when holding command and clicking, as well as with a middle-click on a three-button mouse and the default Tiger mouse settings.
I guess the iframe isn't really relevant, I can imagine situations where a multiple selection would submit a form to the main viewport and this behavior would still be undesirable. Should the command-click new- tab(/new window) behavior be modified on multiple selection boxes?
Confirmed, weird stuff :)
This issue was resolved in r17597, however it is considered as a regression -- see bug 11858.
My fix for bug 11858 does not re-introduce this bug, so we can mark this as fixed!