Just noticed a bug when doing exportToExcel with Java package and percentage symbol (%) in the table. The server side app will crash with an error msg like this link:
After I replace % with %25 in the encoded xml string (modified webix_debug.js), the issue is gone and exported excel looks good.
The same issue could also happen to plus symbol (+) as per the link discussion.
If you have active license - grab Webix 2.0.6 from the support area - it contains the fix for above issue ( the same will be available as part of oncoming Webix 2.1 )
Also, you can patch it manually in debug code by replacing
webix.send(url, { grid_xml : xml }, null, "_blank");