Improved
The 12-lead is laid out like a printed sheet, and the inspect panel fits the window
Before
The paper's scale followed the window's width, so on a laptop the rows were squeezed, tall R waves were cut off at the row above, a band of empty paper sat at the bottom, and the inspect panel ran off the bottom of the screen.
After
The sheet keeps printed proportions, with 40 mm rows, the rhythm strip included, a calibration pulse at the start of each row and marks where the leads change. On a wide screen the inspect panel sits beside the paper without covering any lead, and arrow keys move it from lead to lead; on smaller screens it stays inside the window.