Comments are treated exactly as footnotes - but only if you have decided in the Start Assistant (or in the Document options) that you want to translate them. If you do not want to translate them, they are simply ignored.
If you translate comments, you have to treat them in the same way as you treat footnotes (see Footnotes and Endnotes).
To manually take them over into the translation box, please use the command: Take over comment. (In the case of comments, no special reference is added to the source segment.)
Note: When you copy a source segment which includes comments via the Copy source text command, the comments are NOT copied. When a TU with comments is saved in a translation memory the comments are NOT included.