To remove a gap at the left in the Chromatogram Sanger Reads Editor select the next symbol character or gap after the gap you want to remove and use Backspace or Edit–>press Backspace. You can also select Edit->Remove gap at the left in the left context menu for switching the edit mode on.
After that the edit mode is switched off.
You always can cancel the changes or Actions->Edit->Remove gap at the left.
If there is a region of gaps or it is the beginning of a read, by holding the Backspace key, one can shift a Sanger read to the left. To shift the read to the right hold the Space key, see the Inserting Gap chapter.
You can always cancel the changes by pressing Ctrl+Z.