The following assumes that you are talking about the actual widget "Book Table of Contents" and not the book's content list (which by design shows only hierarchy below the current book). If you are referring to the book's content list, it is not intended to see the full hierarchy here. That is what the navigation links are for, or the separate discussed widget, or the TOC BB-Code's BOOK value.
I identified a bug where for some Maximum Depth settings, the available depth was not being used up. For a partial fix for most values, in
src/addons/vw/vw/_core/view/factory/block/book_toc/vw.php, find:
Code:
$maxparent = floor($maxdepth / 2);
Replace with:
Code:
$maxparent = ceil($maxdepth / 2);
It should be noted that the widget is intended only to have the table of contents relative to the current page expanded. The entire TOC is not expanded in this view.
As for not being able to see the full hierarchy relative to the current page, you can adjust this by modifying your Maximum Depth, in Options > VaultWiki: Navigation > Maximum Depth for Book Table of Contents. The number is a count of possible indents in the table of contents. The indents are filled in equal amounts parent and child (if there are not enough on one side we can go deeper on the opposite side), using the currently viewed chapter as the center point. To always show all available hierarchy, set this number to 15 which is the maximum depth that can be created. If there is a Book with no visible chapters in the hierarchy, then we can expect
Assuming enough depths are available, the widget should fill with siblings first, then child chapters, then parents, deeper children, parent siblings, etc, using the viewed chapter as the center point, until reaching the Maximum Preview amount. Options > VaultWiki: Navigation > Number of Previewed Book Contents.
There is also a bug with some values, especially odd numbers, not moving from center in the expected way. This will be fixed in the next release.