Basic Usage

The day-to-day operations you will use most.

Adding PDFs

Drag and drop a PDF file onto the Desk.
Or click the Add button and pick a file with the file picker.
The same PDF can be added multiple times — each one becomes an independent card with its own annotations.

Drag a card to move it.
Single-click to select a card (it gets a blue highlight). Double-click opens the Editor. Single-click does not open the Editor — this is intentional to prevent accidental navigation.
Click an empty area or press Esc to clear the selection.
Hold a card for half a second to "pick it up" — it floats to the top with a ghost preview.

Just like Windows Explorer:

Ctrl+click (Cmd+click on Mac) toggles individual cards in and out of the selection.
Drag a rectangle across empty space to box-select. A card is selected when its center falls inside the rectangle, so brushing an edge alone does not select it.
Ctrl+A selects every card in the current view.
Drag any one of the selected cards and the whole group moves together, keeping its relative layout.
Right-click the selection to Merge, Move to folder, or Delete all of them at once. Switching folders clears the selection.
Press Delete (or Backspace) to remove the selected cards. Unlike the right-click "Delete" command, no confirmation dialog is shown — use Ctrl+Z to restore them.
Ctrl+C copies the selected cards to an in-app clipboard; Ctrl+V pastes duplicates into the current view (root or the selected folder). Switch folders before pasting to copy between folders. The clipboard does not reach the OS, so cards cannot be moved to other apps or browser tabs (it is cleared when you close the browser).

The Arrange menu in the Desk header

Click Arrange in the Desk header to re-tile the cards into a tidy grid.
Tidy to grid keeps the current order; Sort by name and Sort by date added reorder the cards first.
Only the current view is affected — the root, or the folder you are viewing. Each folder keeps its own layout.

Select a card and press F2 to rename the file inline (just like Windows Explorer).
You can also start a rename from the right-click menu → Rename.
Press Enter or click outside the input to commit, press Esc to cancel.

Dragging one card onto another to merge

Drag a card onto another card. They merge into a single new PDF.
The drop target's name, position, and folder are kept.
Hold Shift while dragging to skip merging and just place the cards together.
To merge more than two PDFs, select several cards, right-click, and choose Merge. The card you right-clicked becomes the first document; the rest follow in reading order (top to bottom, left to right).

Right-click a card → Split (ばらす) (no confirmation dialog — it runs immediately).
Each page becomes its own card, placed in a cascading pattern. The first page sits on top and the last page at the bottom of the stack.
Any annotations (ink, sticky notes, stamps) and rotation on a page are carried over to its card. If you reordered pages in the Editor, the split follows that order.

Right-click a card → Rotate (90° left, 90° right, 180°).
Rotation is stored in a sidecar file. The PDF bytes are not modified, so thumbnail caches stay valid.

The left sidebar shows folders. Drag a card into a folder to file it.
Each folder remembers card positions independently.
Drag the sidebar's right edge to resize it, or click the "‹" button next to the "Folders" label to collapse it.