Modifying "Assigned to me" gadget reset other gadget's configuration

Summary

After modifying the configuration of "Assigned to me" gadget, other gadget's configuration was reset (got lost).

Steps to Reproduce

1. Step a new JIRA 7.2.2 instance
2. Create a sample project A
3. Create a dashboard and add two gadget : "Bubble chart" and "Assigned to me"
4. Configure the "Bubble chart" gadget to the project A and save the configuration
5. Configure the "Assigned to me" gadget to display 5 issues and save the configuration
6. Refresh the page

Expected Results

Both gadgets are configured correctly and display the result

Actual Results

The configuration of "Bubble chart" gadget got lost, user has to reconfigure the gadget.

Notes

• From the Analysis of vkrupach1, confirmed on our side: the difference between Bubble Charts and other gadgets. based on 7.4.2 and 7.10.0 Jira sources, the Bubble Charts is the only configurable gadget that is defined as "dashboard-item" that has the definition tag (see https://developer.atlassian.com/server/jira/platform/dashboard-item-module/) while all other gadgets are defined with "replace-gadget-spec-uri" tag (i.e. backward compatibility with old gadgets development approach). So in Jira prior to 7.8.3 saving settings for "replace-gadget-spec-uri" gadgets clears preferences for "definition" gadgets. This means that configurable "dashboard-item" gadgets developed according to the new approach (i.e. with defintion tag) loose their settings when any other gadget is configured.
• This issue is not present in the latest Jira 7.12.3 and 7.13.0.