Cannot save inline elements on a Subsite in some circumstances

[wernerkrauss]

Module version(s) affected

5.3.6

Description

Silverstripe 5.3.0, Elemental 5.3.6, Subsites 3.3.0

When I have a page on a Subsite (not Main) and there is a Page on Main with the same ID like my Element, I cannot save, cause LeftAndMainSubsites extensions wants to redirect to that page on Main.

Saving works when not inline editable or with any element with an ID that does not fit to an ID of a Page on Main.

How to reproduce

Make a new project with SS5, Elemental, Subsites.

Create a new subsite

Create a Page on the new Subsite and an Element. The Element should have e.g. ID1 which corresponds to a Page on Main

Try to save; check network tab in webdev; it returns a 200 and a blank response; in the answer of the request should be a redirect like

X-Controller | DNADesign\Elemental\Controllers\ElementalAreaController
X-Controllerurl | admin/elemental-area/show/2?SubsiteID=0

Possible Solution

To fix this nasty bug, I added the following configuration:

#hacky fix for getting elemental to work with subsites
DNADesign\Elemental\Controllers\ElementalAreaController:
  tree_class: DNADesign\Elemental\Models\BaseElement

This makes CMSMain controller getRecord() look for an Element instead of a Page

Note: Another possibility (maybe even cleaner) would be to overwrite getRecord() in ElementalAreaController...

Additional Context

CC to @adiwidjaja

Validations

• Check that there isn't already an issue that reports the same bug
• Double check that your reproduction steps work in a fresh installation of silverstripe/installer (with any code examples you've provided)