Issue 2776: ChangeScreen2: Customizable Related Changes Tabs
Status:  New
Owner: ----
Reported by cognifloyd@gmail.com, Jul 15, 2014
It would be nice to make the RelatedChanges tabs more configurable.

For example, in the TYPO3 Neos and Flow projects, we use topics when an issue spans multiple projects. There is typically only one gerrit review per project, but with complementary reviews in up to 10 other projects all sharing the same topic. That means that the Same Topic tab is useless for us unless this line is somehow disabled:
https://gerrit.googlesource.com/gerrit/+/stable-2.9/gerrit-gwtui/src/main/java/com/google/gerrit/client/change/RelatedChanges.java#197

In irc, dborowitz said:
"IMHO rather than adding options to tweak specific tabs in that are, we should have a preference system like we do for dashboards that makes the entire set of tabs customizable"
"it's slightly more complicated than for dashboards because we need placeholders for "whatever is the current project/branch/topic of the change being viewed""

perhaps they could be in the branch: refs/meta/relatedtabs
with one file per tab (tabs included in alphabetical order):
* refs/meta/relatedtabs:10-RelatedChanges
* refs/meta/relatedtabs:20-ConflictsWith
* refs/meta/relatedtabs:30-SameTopic
* refs/meta/relatedtabs:40-Cherry-Picks

The default 10-RelatedChanges file might look like this:
```
[relatedtab]
  title = Related Changes
  tooltip = Same branch changes connected by Git history
  query = dependsOn,neededBy
```

The default 30-SameTopic file might look like:
```
[relatedtab]
  title = Same Topic
  tooltip = Changes with the same topic
  query = status:open project:${project} branch:${branch} topic:${topic} -change:${id}
```

My custom 30-SameTopic file might look like:
```
[relatedtab]
  title = Same Topic
  tooltip = Changes with the same topic
  query = status:open topic:${topic} -change:${id}
```