Mouse and copy

Mouse support covers pane focus, border resize, scrollback, selection, and clipboard copy. The mouse belongs to the terminal you are sitting at, so every setting on this page is read from that terminal's own koshi.kdl.

Focus and resize

Click a pane to focus it. Drag a pane border to resize the panes on either side. A drag moves the border the whole distance in one step, so the layout follows the pointer instead of trailing it a cell at a time.

Disable border dragging in koshi.kdl:

version 1

mouse {
    border-resize #false
}

Scrollback

The wheel scrolls koshi's per-pane history by three lines per notch by default.

version 1

mouse {
    scroll-lines 5
    wheel "scroll-scrollback"
}

Set wheel "ignore" to leave wheel input unused by koshi.

Typing while scrolled up returns to the newest line by default. Set scrollback.scroll-on-input #false to keep the view parked while input still reaches the pane. That one is read by the session, so it is the same for every attached terminal.

Select when an app owns the mouse

Full-screen terminal programs can request mouse input. Press <C-g> to toggle mouse-selection mode for the current client. While enabled, a drag selects terminal text in koshi instead of going to the program.

koshi actions explain core:mouse-select

Hold Shift while dragging to select text even when the program owns mouse input. This does not enter mouse-selection mode.

Copy

Completing a selection copies through OSC 52. OSC 52 asks the outer terminal to write the clipboard, so copying also works through SSH when that terminal allows it. The copy is made where the selection was dragged, so it is that terminal's copy settings that apply.

Trailing blanks are removed from copied lines by default:

version 1

copy {
    trim-trailing-whitespace #true
}

Clipboard policy belongs to the outer terminal. If selection works but the clipboard stays unchanged, check that terminal's OSC 52 setting.