Redmine

• Retain action when applying custom query (changes partly incorporated from #6157)

This was fixed in r4909.

• When custom query is active, show the custom query name (as in issue-lists) on Calendar & Gantt (undo regression added for #2883 -> in r2892)

This was fixed in r4910.

• When custom query is active, query reset-button isn't rendered on Calendar & Gantt (error introduced after Gantt- and Calendar-refactoring for Redmine 1.1.x, reported in #6473 -> fixed incorrectly in r4176)

This was fixed in r4911.

• Move Calendar & Gantt links from issue _sidebar partial to projects-index view (inconsistent location for the links -> move to other global links placeholder awaiting changes for #5920)

Doesn't really belong to the initial idea for this issue and patch and can be much better handled via, preferably, #5920 or alternatively #4603.

• Remove remaining :view_issues_sidebar_planning_bottom hook (has become obsolete)

Up to today the hook is still present. Main reason for this is most likely to be plugin compatibility. By removing the hook, plugins using it need to switch to the remaining :view_issues_sidebar_issues_bottom hook (not to speak about the deprecation process and time that takes, and that for just one hook).
And again: this doesn't really belong to the initial idea for this issue and patch.

I'll look into incorporating the changes from issue #4603 into this patch.

A fresh look at this tells me that it should be kept apart from this issue.

Considering all the above I say this patch has become obsolete; closing as such.