links for multiple selected map elements not shown

regression from 1.8
in 1.8, if multiple elements were selected, links for all of them were shown.

in trunk, links are shown only if one element is selected.

this is inconvenient, and results in the following nasty behaviour :

select two elements, add a link. does not show up in the list. user thinks there's something wrong and clicks the "+" icon a few more times. links do not appear in the list. only when user unselects both items and selects one of them, he sees a bunch of overlapping links added (which now are cumbersome to delete).

extremely nasty usability regression. personally, i would classify it as a blocker because of how unintuitive the current behaviour is. when fixed, would be nice to implement ZBX-1488 as well