In fact, make changes in common to let the player understand the slider component.

Although the DropListElement is a FormElement, its value is represented
by the field options. Therefore, this state must be saved.

It needs row and column to work. (It is using flex in the background.)

Use 'horizontal' and 'vertical'. Which are better terms and also align 
with other element's values.

Also improve conditional border style. The additional dragPreview is 
needed so the dragged item does not have the border.

The width/height of 90% are a preliminary workaround to not produce 
overflow with the border. A better solution would be good.

This element has a list of string as editable options. Those strings 
form draggable elements which may be reordered or moved between 
different DropList elements.

Also refactor option change logic to allow any property not just the 
text property.

This works similarly to the standard radio group, but has a fixed 
horizontal layout with images above the options.

* Change the detection of the parent element to determine whether the
audio/video player is running in the aspect-editor or the aspect-player

* Add magnifier properties to `ImageElement`
* Set used value at `UnitStateService`
* Bypass parsing error of distpacker

Wait until a solution is found for the distpacker when parsing "'url('+ (image.src) + ')'".

Use flex to position image and text below one another. Don't use any 
image scaling setting. Now the images grow but don't shrink.

There were some things missing when renaming questions/answers to 
rows/columns. Now everything is properly named.

* Show current and maximal runs in control bar

This function will be implemented differently.

* Refactor markable text
* Prevent multiple selections (feature is only supported in Firefox)

To not have the same name as likert rows and cause issues on the props 
panel.

The condition did not respect the case of null value.

And avoid global styling.

This way empty paragraphs still produce an empty line.
Not possible to do inline because CSS pseudo classes do not work inline.

This way the color-input element can read the color and show the correct 
preview.