Custom Tabulator

[kboshold]

I want to display a character of the Unicode private range as Tabulator ("\t"). Therefor i created a custom highlight rule:

this.$rules = {
	temporarySpace: [
		{
			token: ["text.xml.customTab"],
			regex: "\uF6D9", // just a random character 
			onMatch: function(val, state, stack) {
				// every "indent" will be in a single span
				return [{
					type: "text.xml.customTab",
					value: val
				}]
			}

		},
	],
        // .....
};

To get the "customTab" wider, I tried two things:

1. I used CSS to make the toker wider. But in this case you get trouble with the selection. It looks good, but as soon as you type/delete, it will add/delete the content at an incorrect offset.
2. Returning \t instead of val. This also leads into the same error or 1.

How can i make a "token" wider or add an character that will be shown like a tabulator (I also need a different background on this character)?