If you want to stretch the Layers palette, tear it off the other docked palettes, then click and drag the lower right corner. Not that anyone would want to, but we can stretch the Layers palette to fill the entire Painter screen’s width and height.
Another way to make the Layers palette longer, is to hold your cursor over the “line” where the inside of the palette meets the lower frame, just above the icons. Then click and drag down to make the palette longer, or up to make it shorter (up to the minimum height).
In Painter IX.5 and earlier versions, it will take a few tries before you can “grab” that line.
In Painter X, it’s much easier. When we hold the cursor over that “line”, a new cursor appears. It looks like a thin black line with black arrows pointing up and down. When that cursor appears, click and drag up or down to change the height of the Layers palette.