==== Motivation
The current block form is confusing in terms of which options are //partial// and which ones are not. It is unclear which options apply only when "Partial" block editing is selected and which ones apply when "Sitewide" block editing is selected. The software understanding also differs from the user mental model. To mitigate this we want to make it more explicit which specific action blocks relate to which action blocks.
==== Proposed solution
|Current UI|New UI - Sitewide blocks|New UI - Partial blocks|
|{F34409458, width=300}| {F34486504,width=300}| {F34486506,width=300}|
* The //Actions to block:// label is changed to //Block type//
* The //Editing// checkbox is replaced with radio buttons for //Sitewide// and //Partial//
* **For //Sitewide// blocks:**
** Show sub-text (always visible): //Blocks editing on all pages and namespaces. Also blocks default actions (See help)//
*** This help page will need to be created and should explain what kinds of actions are blocked on sitewide.
** Sitewide radio button is selected by default.
* **For //Partial// blocks:**
** Show sub-text (always visible): //Allows you to select pages and namespaces to block. Doesn’t block default actions but lets you block certain specific actions.//
** Until the //Partial// option is selected, no partial block options are shown (including the Pages and Namespace widgets).
** When user selects the //Partial// radio button - show Pages and Namespaces widgets and relevant specific partial blocks.
** All block actions appear indented from the //Partial// radio button, per the mocks.
* **For //Block details//**
** The //Account creation//, //Sending email//, and //Editing their own talk page// checkboxes will live under the label //Block details//.
* ~~All of this work happens behind a feature flag.~~
Note that we will need to be careful not to break the behaviour of the block parameters. E.g. the current 'Editing' checkbox currently maps to the wpEditing URL param.