Hide Inactive product variants

Hi,

When the "Display out of stock products" setting of the HikaShop configuration is turned off, the dropdowns will only display the values if there is at least one variant using the value.
If that's not the case, then maybe it's a bug and updating HikaShop would be a solution.

But that also means that you will be able to select variants which are not available if the values of the variant are necessary for other variants.
For example, if you have 2 colors (blue and red) and 2 sizes (L and XL), and you disable blue L and red XL. You'll still see all the choices in the dropdowns as otherwise you wouldn't be able to choose the other variants.
To avoid that, if you have two characteristics in your products, you can use the "table" display of the "characteristics selection method". That will display the characteristics selection in a 2d table where only the available variants can be selected.
And with the recent versions of HikaShop, there is also the "list" display which displays a list of available variants.
If you don't have the "table" display when you select it and that you have two characteristics in your product, then it means that your template must have an override on the "show_block_characteristic" view file preventing you from seeing the table display.
Try switching temporarily to the default template of Joomla to confirm that it comes from the template overrides.