Wood will expand and contract across the grain, and a wide panel made of solid wood could change width by a half of an inch, warping the door frame. By allowing the wood panel to float, it can expand and contract without damaging the door.
Put trimmed and cleaned green beans in the steamer basket, set over the boiling water, cover, and steam until tender to the bite, 3 to 5 minutes (depending, again, on how crisp or tender you like your green beans).
Cut the head of cabbage in half, and then cut the two halves in half to make four wedges if your recipe calls for wedges. Add the cabbage to your steamer basket and place a lid on top to hold the steam inside. Steam for five to eight minutes for shredded cabbage and 10 to 12 minutes for wedges. Remove the pot and steamer basket from the heat, and remove the cabbage from the basket with tongs.