Modal is used on an action after editing in controlpanel

[mauritsvanrees]

Plone 6.0.5. Default behavior:

• Create a Classic Plone Site.
• On the home page, click Contents.
• This opens a new page, as expected.

Now try this scenario:

• Go to Site Setup, Actions control panel.
• Find the Contents action under the Object Actions, and click to Edit.
• Scroll to the bottom. Note that "Settings for pat-plone-modal" contains an empty dict {}.
• Do not change anything, just click Save.
• On the home page, click Contents again.
• This opens in a modal, very much unwanted.

This is probably happening since https://github.com/plone/plone.base/pull/27 was merged. This was released in plone.base 1.0.3, which already is used since Plone 6.0.2.

Solutions I see:

1. Change the default value of modal to an empty string, instead of {}.
2. Change whatever code is using this property, so an empty string does not trigger using a modal. But I guess this is the silent assumption (or maybe it is documented): if the modal setting contains at least something, even an empty dict, then this is the current way to signal to Plone that a modal should be used. If you just want a modal, and are happy with the default modal settings, then this makes sense.

I would say we go with solution 1. But if someone thinks solution 2 is better, I am happy to hear it.