Gantt Cloud allows editing Issue links directly from the Add-on page via Issue dialog. Only "blocks"/"bloked by" type of links can be added or removed. The other links used in JIRA are ignored as not relevant for chart rendering. To add dependency between two issues simply click on one of them so the Issue dialog will open. Then, click the plus icon on the right hand side of the "Issue Links" title section. Using mini editor that will open right beneath the title you can add new link. To remove exiting link, hover on the linked issue title in "Issue Links" section and click the trash icon on the right. Gantt chart will be refreshed instantly every time the link is added or removed and change will be propagated to the JIRA instance accordingly.