the idea is that once you initiate the transfer with CTRL+Leftclick the process should be fixed to that single type of item or bulding. (maybe with an option in the settings to enable/disable this)
It happens to me every now and then when I empty my furnaces and gather the iron plates, that I often hit also the burner miners and collect the coal.
Of course, you might say to improve my aim to prevent sliding off the furnaces. But it would be very nice to have such an option.

Thanks and cheers,
Joe