Selecting lines of code

It's quite tedious selecting lines of code with a finger. It seems to me that the slightest movement while executing a long click in order to select the first of a block of lines results in that line not becoming selected. Subsequent lines are, of course easy to select and deselect once that first line has been successfully selected. A little square box in the margin against each line could be ticked or unticked to cause the selection or deselection perhaps?