The Comment Block item is available via the Reformat Text button on the collection toolbar and via the Format menu, except when the Recycle Bin tab is active.
If the current clip is being syntax colored by a syntax coloring scheme that contains a character string for single-line comments then Comment Block automatically uses those characters. If there is no selection then the comment characters are inserted at the first non-whitespace character on the line that the cursor is on. If you’ve made a selection that flows along with the text then the comment characters are inserted at the first non-whitespace character on each the line. Essentially, indentation is preserved after lines are commented out. Blank lines are not commented out.
If you’ve made a rectangular selection then the comment characters are inserted on each line covered by the selection at the leftmost column in the selection, even if the line is blank.
If you prefer the comment characters to be at the start of the line or the left hand edge of the rectangular selection, use the Quote Block command instead.
If the syntax coloring scheme does not define characters for single-line comments, but does define characters for multi-line comments, then Block|Comment inserts the characters that start a multi-line comment in the same way that it inserts characters that start a single-line comment. It then additionally inserts the characters that end a multi-line comment at the end of each line or at the right-hand edge of the selection if it is rectangular.
If the current file type does not use a syntax coloring scheme, or the scheme does not define any characters to comment out something, then Comment Block asks you for the characters used to start a single-line comment. Those are then used in the same way as single-line comment characters from a single coloring scheme. You can tick a checkbox to make AceText remember the comment characters you provided. It does so separately for each collection while you have the collection open.
If only one line was selected or if there was no selection then Comment Block moves the text cursor to the next line. This allows you to quickly comment out multiple lines without having to select them.
To remove the comment characters, use Uncomment Block or Toggle Comment.
You can use Comment Block on lines that are already commented out. Those are then doubly commented out. This allows you to comment out a large block in which some lines are commented out and then uncomment the whole block with Uncomment Block. The lines that were originally commented out will still be commented out.