EDIT

It would also be possible to show the icon in the first column no matter what property is shown in the first column. If we add another column the only use case we have right now is the deduplication. So in most cases the column will be empty. I would prefer showing the icon in the first column. Plus, it is a rare case that the user would moveor hide the first column as it is some kind of identifier for the whole row object.

I think we can will with this implementation though I still think that a separate column would be even better.

Is it maybe possible to put the symbol to the left side of the cell? Then it is really at the beginning. By the way the current solution does not work with checkbox columns as first columns, the symbol is not shown there.

The icon can be put in any corner or even centered. But, at least for now I haven't found an easy solution, if we put it at the beginning it will be drawn above the text.

In case of the checkbox column there is only the option to draw the icon above the checkbox. However, I think this it is a very rare case that someone moves any checkbox column to the first column. Additionally the rows are colored according to their deduplication state as a secondary hint.

If it is not possible to put the symbol beside the text we should better leave it where it is.