Comments module affects CMS layout

[raissanorth]

Within the CMS' split mode, any items nested underneath the Comments tab that contain any or none items cause the Content | Settings | History navigation to stretch into the preview area:

This issue arises with both the simple and the starter theme.

Versions used:

silverstripe/cms                          4.1.x-dev 7dea009  
silverstripe/comments                     dev-master 4385299 

[NightJar]

The grid fields for comments simply have too many columns, which pushes the width of the containing tab out - altering the 100% of all the parent containers, resulting in the heading toolbar following suit.

This also results in the bulk editing tools being inaccessible by sight/mouse (behind the preview, as such).

I'm not sure what to do about this, as experimentation thus far has seen that only restricting the summary fields on Comment helps.

[clarkepaul]

Similar issue here silverstripe/silverstripe-admin#498

[clarkepaul]

For this issue @ScopeyNZ is creating a fix for the tabs not extending the panel.

I've created two other issues to capture the comments table not being responsive and other layout issues.
Related #250
Related silverstripe/silverstripe-admin#528

[robbieaverill]

Fixed in silverstripe/silverstripe-admin#527