Strange text added when I move mouse focus to another window.

[ShawnMcCool]

I'm using the app fine, then when I move my mouse to another window, a chunk of text just gets added wherever the cursor is located.

Ubuntu
Wayland / Sway WM

[ShawnMcCool]

I'm seeing it happening with GhosTTY and NOT with Foot. So I'm exploring that angle further.

[darrenburns]

This is a bug in Ghostty or Textual (the TUI framework Posting is built on), or possibly both.

There's a terminal protocol which allows terminals to report the pixel coordinates of the mouse cursor (as opposed to the usual cell coordinates within the terminal's grid of characters). Ghostty is currently sending negative numbers for these pixel coordinates when the cursor moves out of the terminal window. See those -2s in the output, I believe that's a negative x or y coordinate reported by Ghostty.

Ghostty shouldn't be reporting these coordinates, but Textual should probably be resilient against them. I'll try to make a PR to make Textual resilient against this.

[hollowonepl]

This is not a bug in Ghostty, it's also in other terminals (like system terminal in MacOs I've been testing it with, and also terminal multiplexers Zellig. Basically if a terminal accepts mouse input (left clicks for example) and converts them into ansi escape codes being sent to terminal, posting treats them as keyboard input and shows them as an output in its text input boxes.

[gitmpr]

I’ve tracked this down to Ghostty’s default window padding interacting with pixel-precision mouse reporting (SGR 1016).

When Ghostty has padding, the mouse can move through an area inside the terminal window but outside the character cell grid. In this zone, the reported pixel coordinates can go negative, which then leak into Posting/Textual inputs as sequences like:

[<35;363;-2M

From Ghostty’s source i've gathered that the default config for padding is set to:

window-padding-x defaults to 2 points (left and right)

window-padding-y defaults to 2 points (top and bottom)

You can set the following in your Ghostty config to disable the padding complete, and see that the issue won't happen then:

window-padding-x = 0
window-padding-y = 0

https://ghostty.org/docs/config/reference#window-padding-x

You must start a new terminal window for the change to take effect.

This behavior isn’t unique to Ghostty. Any terminal that implements SGR-Pixels (1016) and reports coordinates outside the cell grid could potentially send negative values. While this can be a nice feature for more precise UI interactions, applications like Posting/Textual should handle these cases gracefully rather than letting raw sequences show up in input fields.

[darrenburns]

This was fixed in 2.8.0