The whole Technical Reference is embedded in this page -- nothing is fetched and it works offline. This panel shows it as a real document: it can be read in pages, collapsed like Word's outline view, searched with a grouped results list, and jumped through by double-clicking words.
The keys below act on the manual, so click inside it first -- while the focus is in a text box (the Contents search, the tree's Filter) every key belongs to that box instead.
Reading modes. The mode button in this title bar names the mode you are in; clicking it switches to the other. Window -- how the manual opens -- is a single page zoomed to fill the space up to the Contents pane. Pages lays the document out as facing pages instead: as many whole pages as the window fits, each at the manual's own page width, running left to right and centred with equal margins. Nothing re-wraps in either mode, so a page holds exactly what the printed page holds.
Turning pages. In Pages mode the wheel turns one page per notch, → and ← move one page, and Page Down/Page Up move by as many pages as are showing. There is no vertical scrolling in this mode, so the vertical scrollbar becomes the page control -- drag it to move through the document. End goes to the last page and Home to the first (with or without Ctrl). In Page mode scrolling is ordinary and the same two keys go to the end and the start of the document.
Zoom. Ctrl+wheel zooms the manual between a quarter and four times, anchored on the text under the pointer. Line breaks never change -- the page is a scaled copy of itself, which is why it is instant. In Pages mode zooming shows the same pages larger rather than re-flowing them into more or fewer; the number of pages across is re-fitted when the window resizes or the Contents pane opens.
Jumping to a keyword's definition. Double-click any word -- anywhere, in ordinary prose as well as in a syntax listing. If a bookmark of that name exists, the view goes there: a bookmark is the author saying "this is where this is defined". Otherwise it goes to the syntax line that introduces the word as [keyword. Cross-references are skipped on the way -- a hyperlinked [keyword points at the definition, so it is never the definition itself. Matching is case-sensitive, like TOPAS's own syntax. Where the manual has made a keyword plural by typing an s after it, that s is dropped -- the keyword's own styling is what says where it ends -- so double-clicking the plural still finds the definition. In Pages mode the definition is placed on the same page of the spread that you double-clicked in, so your eye does not have to move; the line itself is highlighted until you click, scroll or turn the wheel. A word with neither a bookmark nor a bracketed syntax line simply does nothing.
Finding every use of a word. Ctrl+double-click a word instead, and it is put into the Contents pane's search box and searched for -- the Contents pane opens if it was shut. Where the plain double-click answers "where is this defined", this one answers "where is it used".
Contents (the ☰ button) lists every chapter and section, with −/+ at its header to close or open all chapters at once. Drag its left edge to widen or narrow it; it starts at its usual width each time the document loads. The entries whose text is currently on screen are highlighted, and the chapters containing them with them -- so the pane says where you are as you read, including when the chapter is collapsed and its own line is all you can see.
Searching. The box at the top of Contents searches the whole document -- type and press Enter, and the chapter list is replaced by every match, grouped under the section it falls in, with a count per section. Aa toggles case sensitivity. Clicking a result jumps to that occurrence, expanding its section first if it was collapsed; every match is highlighted in the document at once. Hits in the manual's own table of contents are listed last, so they can't bury the real ones. The × beside the box clears the search and brings the chapter list back -- as does Esc while the cursor is in the box. The browser's own Ctrl+F still works and is quicker for a single jump -- this is for seeing where a term occurs across the whole manual.
Collapsing sections works like Word's outline view. Click anywhere in the document to put the cursor in a section -- its heading is highlighted. − in this title bar then collapses that section; pressing it again, on a title already collapsed, collapses the section above it, so repeated presses fold outwards. Every heading also carries its own −/+, and + there expands the section one level at a time. Clicking a star in the tree clears all collapsing, so a keyword jump always lands in a readable document; following a cross-reference inside the manual opens only what it needs to.
Stepping back and forward. The ←/→ arrows in this title bar step through the last 20 places you have jumped to inside the manual -- stars, cross-references, Contents entries, search results and double-click jumps all count. They are greyed when there is nowhere to step. These are separate from the browser's own Back and Forward, which move between this page's views (the tree, the first page, the tree's Help).
Dark mode inverts the manual along with the rest of the page, and text that would come out too dark or too bright to read against the inverted background is pulled back into range -- so reference lists and coloured headings stay legible rather than turning black on black.