Forge

By utilizing the Server Side Dropdown with Lazy Loading custom Forge component, OutSystems developers can enhance their applications' dropdown functionality, delivering an improved user experience with optimized performance.

"I understand that EncodeHTML is a security way to avoid xss, but in some cases that words contain accents, the dropdown is hiding the values when disabling the dropdown."

I reused the platform's native dropdownsearch, and implemented the optional encode html option

For more details see demo.

Optional html coding implementation, if I disable an item that was selected, and the item that was selected is an accented word, its value will disappear from the dropdown.

Enhanced Dropdown block, with search functionality.

Drag the block to your screen and set the ItemList parameter structure with your list. Use the SelectedItem parameter to define a pre-selected item.

Use the OnSelect event to assign the current value selected to your local variable.

For advanced scenarios, use the AdvancedFormat parameter. To check the options available, read the official documentation:
https://github.com/jshjohnson/Choices