Thanks for putting everything into tutorial
For future users "please subscribe, smash that like button and don't forget to turn on notification to get latest updates" 
Seriously man, thanks for vlogging all your stuff
I'll be reviewing your homework Csongor. 
Another live stream done, a form, form submittion, and miscallenaous buttons are working. Very happy with the progress.
I have a few questions, but could be more HTML/CSS questions that uibuilder. I can ask them here as well, but maybe there should be a generic "uibuilder tips & tricks" topic, or separate topic for each?
- Are there any good examples of a fly-in status message like the toast message in ui-notifications? I assume this would be some floating div with some javasript that moved it out of view after a timeout period.
- Any best practice of handling validation errors with uib-element Simple Form? Error show up above of below the respective form fields?
By all means start a "UIBUILDER Tips & Tricks" tag if you like. 
Never tried that but in general, you'd create the div off-screen and animate it into view.
The default brand css gives some simple error highlighting I seem to remember so check out the forms section of the css so you can see how that is done. CSS classes such as form:invalid xxxx should allow you to identify inputs that are invalid, maybe input:invalid?
You might be able to use things like input:invalid + div to select an adjacent element to display/hide. ref.
Yes, now I remember the :invalid option. But there is no place for the validation message to be included in the simple form JSON right? I mean something like this:
{
"id": "userid",
"type": "text",
"required": true,
"label": "User ID:",
"value": "info@node-red.org",
"error": "User id already exists, pick a different userid"
},
I am just saying this, becuase otherwise I would need separate uib-elements probably one for each field to display/hide the validation error divs. Maybe the code can assume that there is a ID xxx_error or xxx_notification where xxx is the ID of the entry field.
I will try to add an error blank to forms in the future. You could easily insert something dynamically though if you wanted to.
You mean as a separate uib-element to populate the "error div"?
Yes, though you possibly want just a uib-tag if inserting a single tag. But you might actually want to insert a placeholder div on all inputs in advance.
At present, there is no zero-code way to update multiple elements with the same addition so you would want to capture the output from a uib-tag and amend it to use the update method instead of replace. With update, you choose the parent as usual but in this case, that would be a CSS Selector that would select - all inputs div wrappers lets say (you'd perhaps need to play with things to get the right selection). Then you should (I've actually not tried this myself I don't think) be able to append a new div marked with a class to hide it. I think this would be best done with some simple front-end JavaScript as it would be more responsive but you could do it from Node-RED as well I think.
I'll try to find some time to run up an example.
I should also have said that you should remember that you can always grab a copy of the current HTML from the front-end using a simple command from Node-RED:
You can pass that to a uib-save node if you want to have it saved into a file.
This would let you play with the HTML after using no-code to set up the basics.
Maybe better than an example. Here is the content of a function node. Put this immediately after the uib-element node that produces your form.
It manipulates the low-code JSON output to add in the extra divs. Adjust to suit.
// grab the output that contains the child `div`s of the actual form (the rows of the form)
const frmInputs = msg._ui[0].components[0].components[1].components
// Walk through each row
frmInputs.forEach((inp, i) => {
// Work out the ID for the actual input for this row
let inpId = frmInputs[i].components[1].id
// Calculate a matching ID for the error div
inpId = inpId.replace(/r(\d+)-.*$/, 'r$1-err')
// Add a new child div to this row
inp.components.push({
"type": "div",
"id": inpId,
"attributes": {
// You can use any class you want of course. Starting with all divs hidden
"class":" hidden inputerror",
},
// You might want to use an extra input array to define standard text for each
// error msg div.
// slot: stdErrorText[i],
// You probably also want to not put an error div on the button row.
// but I'll leave that as an exercise for others. :-)
})
})
return msg
It will work with ANY form output from uib-element. All I would say is that, because I'll be needing to update uib-element form output in the future, you might need to check that this still works in future releases. I always try to avoid potentially breaking changes but it is possible that this could be one, not totally certain.
Because each form row now has a div to contain error text below the input with a unique ID, you can now easily change the classes or it might be possible to come up with a selector that targets all error divs where its previous sibling has the :invalid pseudo-class. ChatGPT probably knows! 
If not, you can use the invalid event and change classes dynamically.
Let me know how you get on. I will certainly be using the learning from this thread to do future updates to uib-elements form output so that you don't need all the messing. I knew forms were a bit simplistic and needed work, this helps focus on what needs doing.
But as you can see, the joy of the no-code output being standard JSON is that it is possible to manipulate it however you want.
OK, even better.
// grab the output that contains the child `div`s of the actual form (the rows of the form)
const frmInputs = msg._ui[0].components[0].components[1].components
// Walk through each row
frmInputs.forEach((inp, i) => {
// Add a new child div to this row
inp.components.push({
"type": "div",
// You might want to use an extra input array to define standard text for each
// error msg div.
// slot: stdErrorText[i],
slot: 'ERROR',
// You probably also want to not put an error div on the button row.
// but I'll leave that as an exercise for others. :-)
})
})
return msg
So we've got rid of the ID's & attributes because we don't need them at all. Here is some CSS that will show the error divs of EVERY invalid input in the form and hide them otherwise:
form :invalid + div {
display: block;
background-color: red;
}
form > div > div {
display: none;
}
