When page is performing form update, entry in multiselect is ellipsed till no extra symbols expect ellipsis are seen.
Titles on hover are still correct.

Upon my observations it can be reproduced, when "form_refresh" is performed in edit form. I found it in edit forms for hosts, templates, host prototypes.

Steps to reproduce:

1. Go to Configuration->Hosts->Edit
2. Select one or more groups in multiselect
3. Go to Macros tab -> Inherited and host macros
4. Go back to Host tab

Result:
All entries in multiselect are ellipsed.

Expected:
Entry name in multiselect should be ellipsed only when it is too long.