Custom dropdowns (specify your own list of options)

Feature request!

Often times I create custom blocks that take an input that is basically a flag with several options. For example, suppose I have two behaviors I want to make into custom blocks - one which sets a "MP" value of every character with HP > 0 to its maximum value, and one which sets it to zero. Now since these both share a lot of behavior (specifically, looping over the list of characters and acting on each one who has HP > 0), it's simplest for me to make this into one custom block, and have the caller specify which action should be used. That custom block definition would look like this:

However, typing in those values is tedious, and prone to error - what if I make a typo? In a sense, it makes my custom block "un-Scratch-like": it makes my programming rely on typed syntax, already an inconvenience, and therefore makes it vulnerable to syntax errors!

Here's another example: Suppose I define a sort-of "object" system, similar to what you saw in the example above. I make a list of character names, and I create a custom block which changes the value of a given field on the character with a given name. This might look something like the following:

Of course, it's again clear that the "field" input can take on one of several values, and that this value changes the behavior of the custom block.

In cases like these, the problem of un-Scratch-ness could be avoided by making use of a simple new feature: the ability to define custom dropdowns. The concept is quite simple: the dropdown has a list of options that you, the creator of the custom block, specify.

The UI for how that should look needs discussion, but I have one idea: You press a button to add the dropdown input to the custom block in the "Make a Block" dialog. Then the input is automatically focused. Then, instead of transforming into an input which you type in to rename the input, it shows a menu beneath it containing several options: name of the input, type of the dropdown, and if the type is "custom", preview of the dropdown, which can be edited to add the options you want. (Of course, clicking the dropdown from the block in the "Make a Block" dialog would open that form again.)

Part of the reason I suggest this idea is that other options for inputs would fit in very nicely as well. For example, suppose we used this UI for every kind of input. Then there could be another row, beneath the name row, for setting the default value of the input - again, making the user's own custom blocks more similar to and as useful as real Scratch blocks.

Thoughts? I'm happy to discuss and clarify any of my ideas here.

No files, tests, or entry points are named. Start by reviewing the proposed custom dropdown behavior and the Make a Block dialog discussion, then establish the UI and option-list requirements; done should mean custom block creators can define dropdown options without typing each value manually.