Hi,

You can add more this code to Customize > Custom CSS to hide this category on Categories widget:

.widget_categories ul li.cat-item-123 { display: none;  }

Note Important: You need to change number 123 on the above code to category ID of category slider.

You can read this guide to know how to find category ID of a category.

Best Regards,

PenciDesign

Hi,

I think you should use featured category to select the posts you want to display for your slider. Please do following steps:

1/ Create a new category - Example:  "Slider"

2/ Add all the posts you want to display on the slider to this category.

3/ Go to Customize > Featured Slider Options > on "Select Featured Category" > select category "Slider" and check to "Hide Featured Category" to hide this category appears on your site.

Best Regards,

PenciDesign