Toggle visibility of comments & summary lines
Be able to toggle visibility of full comment lines (//) and summary lines (///) for better code visibility. When these are hidden a one-pixel line in the comment color is shown between the lines. A quick hotkey will toggle all visibility, or hovering over a line will show a tooltip with the comment contents.
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Well, it would be even better if the IDE would also be able to format documentation comments instead of showing XML directly.
But I think that usually it would be nice to show first line anyway (as it is done for documentation comments). An alternative display would be to put a comment icon at the beginning of the line.
And since we are taking about comment formatting, then having some styling options would be nice.