The sliding part will come out but you will need to remove the felt channel it rides in to get it out. Open the window fully then pull the felt out of the window frame as much as you can until it meets the open glass. Slide the glass AND THE FELF as if you are closing the window as far as you can. Holding the channel in place and slide the glass back open so the far edge of the window exits the end of the now repositioned felt. Keep repeating until you remove the channel. With the lower felt removed the glass will sit lower in the window frame and the upper edge will clear the top of the frame so the window can be removed.
Keep a second set of hands close by since the window can fall out of the frame as soon as if is clear of the felt and drops deeper into the frame.
If the channel is difficult to slide lube the window frame with some soap which is easy to clean out later.