Method for operating a door drive connected to a leaf of a building door, wherein the door drive can be operated in an automatic mode (A, I) with an automatic operation in which, in response to a control signal from an end user, an opening operation of the door is carried out, then waiting for a stay-open time (t2.1) and thereafter a closing operation of the door, and wherein in a door closer mode with a door closer function in which an open position of a manually or otherwise non-automatically opened door is detected, a stay-open time (t2.2) is waited for and subsequently the door is closed again by motor drive up to a closing end position, wherein the door closer mode with door closer function can optionally be a semi-automatic mode with door closer function or a manual mode with door closer function, wherein in the manual mode the leaf of the building door can be moved manually, without drive by the door drive, in the opening direction, comprising: operating the door operator in parallel in the automatic mode and in the door closer mode with door closer function, detecting a manual operation of the building door by detecting a change in position of the leaf not initiated by motor drive, monitoring a position of the leaf by means of a position sensor, wherein a manual actuation is detected by detecting a position change not initiated by motor drive, assigning and/or performing different stay-open times (t2.1, t2.2) for the different operating modes and optionally also for different control signals, wherein the automatic mode is performed with a longer stay-open time than the door closer mode with door closer function, wherein the stay-open time (t2.2) in the semi-automatic mode with door closer function corresponds to the stay-open time when a manual actuation of the door from the closing end position in an opening direction is recognized as a start signal for an automatic driving of the leaf in this direction of movement, a complete opening of the door is carried out by the door drive and subsequently the door is closed again, and wherein the stay-open time (t2.2) during the manual door operation with door closer function corresponds to the stay-open time when the door is closed again from this opening position after manual movement into any opening position. operating the door operator in parallel in the automatic mode and in the door closer mode with door closer function, detecting a manual operation of the building door by detecting a change in position of the leaf not initiated by motor drive, monitoring a position of the leaf by means of a position sensor, wherein a manual actuation is detected by detecting a position change not initiated by motor drive, assigning and/or performing different stay-open times (t2.1, t2.2) for the different operating modes and optionally also for different control signals, wherein the automatic mode is performed with a longer stay-open time than the door closer mode with door closer function, wherein the stay-open time (t2.2) in the semi-automatic mode with door closer function corresponds to the stay-open time when a manual actuation of the door from the closing end position in an opening direction is recognized as a start signal for an automatic driving of the leaf in this direction of movement, a complete opening of the door is carried out by the door drive and subsequently the door is closed again, and wherein the stay-open time (t2.2) during the manual door operation with door closer function corresponds to the stay-open time when the door is closed again from this opening position after manual movement into any opening position.