editstyle.ui - Hiding or showing left-hand list (pageList) reverts to default size
1) Click the Format menu, Style... option
2) Change the width of the dialog box (larger only)
3) Click the arrow button at the bottom left of the dialog box.
4) The dialog box is now back to its original width. Your changes to the dialog size are lost.
This interacts with this issue: https://musescore.org/en/node/287863 because after clicking the button, the dialog box is no longer user-sizable.