Hi,
I‘ve already reproduced your issue in Microsoft Edge 42/44 version in Chinese/Korean system locale, but works fine in English Locale.
This issue was reported to R&D as JIRA TW-50057, and had already been fixed in ThingWorx 8.5.
Here are the solutions for you:
1. Still use Thingworx 8.4 with IE 11/Edge, please change system locale to English (Control Panel>Region>Administrative>Change system locale) and restart workstation.
2. Use Chrome instead for Thingworx 8.4
3. Upgrade to Thingworx 8.5
Thanks,
Steven