When creating a Tag, Stackla will automatically generate a slug which is then used to add a CSS class to relevant Tiles in Stackla displays.
The slug is generated based on the Tag Name - removing capitalisation, special characters and any spaces.
For example if you named your tag Test tag - 201421 the slug will automatically be named testtag201421.
You can override this automatically generated slug by checking the "Custom Slug" checkbox on the Advanced tab when creating a Tag and entering a value in the text field above.