Files and Tabs

Everything you open in Zasper, whether a notebook, a file, a diff, the Help page, Settings or What’s New, opens in a tab. Terminals are the exception: they open in the panel under the editor, as Work in a Terminal describes. This page covers how each kind of file opens, how tabs behave, and what Zasper remembers between visits.

How Files Open

Markdown

A Markdown file opens in Edit. The buttons in the strip under the file’s path switch it to:

• Preview, which renders the file the way a markdown cell is rendered, with GitHub Flavored Markdown tables and task lists, and LaTeX through KaTeX;
• Side by side, which shows the source and the preview together. The preview scrolls along with the source, and catches up between keystrokes so typing stays responsive in a long file.

Switching to Preview and back keeps the editor’s undo history.

PDF

A PDF is shown with the viewer built into your browser, so zoom, search and page navigation work as they do for any PDF there. Download saves a copy. A browser without a built-in PDF viewer still offers the download.

Tabs

The Launcher is always the first tab and has no close button. When you close the tab in front, the Launcher comes forward; closing a tab behind it leaves the one in front where it is.

Beside its kernels, the Launcher lists Recent files, the last six you opened in this project that are not open now. Running lists the server’s kernels and terminals, including a kernel whose notebook has no tab open, which is marked no tab. Click a kernel to open its notebook, or shut down a kernel or terminal from its row.

A dot on a tab means it has unsaved changes. Closing it asks whether to save, discard or cancel, and closing several tabs at once asks about all their unsaved changes in one dialog.

Right-click a tab to close it, the others, those to its left or right, the saved ones, or all of them, or to Copy Path and Reveal in File Explorer. The close actions have shortcuts too; see Key Bindings.

Reopen Closed Tab (⌥⇧T / Alt+Shift+T) brings back the last tab you closed, and pressing it again goes further back, up to ten tabs. It reopens files, notebooks, diffs, Help, Settings and What’s New. A data tab, a terminal or a language server’s log is not brought back.

Toggle Sidebar (⌘B / Ctrl+B, or the button in the top bar) hides the file explorer and the other side panels to give the tabs the whole window. Dragging the sidebar narrower than its minimum also hides it, and choosing a panel brings it back.

Tabs Are Remembered

Zasper remembers which tabs you had open in each project and reopens them when you come back, even after closing the browser. A remembered tab reads its file only when you first switch to it, so a long list of tabs doesn’t slow down opening Zasper. A notebook reconnects to its kernel if that kernel is still running.

Some things are deliberately not brought back:

• Terminals. Every terminal connection starts a new shell, so a restored terminal would be empty.
• Unsaved edits. A restored tab shows the file as it is on disk.
• Data tabs. A table opened from a kernel, and a language server’s log, are left closed. Open them again from where you found them.

The list is stored in your browser, separately for each project folder, so opening a different project doesn’t bring back tabs from this one. If two browser windows are open on the same project, the one that last opened, closed or switched a tab is the one Zasper remembers.

The Help Tab

Press F1, or choose Keyboard Shortcuts from the command palette, to open the Help tab. It lists every command that has a shortcut, grouped by category, with a box to filter them. Its About section shows Zasper’s version and platform, which is what a bug report needs, and Copy details copies them. It doesn’t include your username or any folder names, so it’s safe to paste into an issue.

The What’s New Tab

After you upgrade, Zasper opens the What’s New tab once, with the release notes of the version you are running and of every version since the one you were on. What’s New in the command palette opens it again, and Every release links to the full changelog.