Proposal to allow custom blocks to show error messages

[NOTE: the problem is solved by the "try catch library". So, just ignore this post :grin:]

I propose to show up a popup ballon when a RESULT block is executed inside a command custom block. By adding this possibility, developers of libraries will be able to add error messages to their custom blocks.

For an example, see this project.

this does not require any js, as it is in the primitive block

use the try catch library, it includes a proper error block and blocks for detecting errors

I didn't know it. Thanks