Compile, run, and diagnostics

Run in place

That toolbar cell changes shape with the file type:

If the program needs keyboard input, a send box appears in the bottom panel — type a line and press Return to feed it in.

Stopping

■ Stop lives at the far right of the bottom status bar (just left of the panel-toggle icon) — it only appears while a program is running. If a program will not stop, press Back to leave the window.

Errors are drawn on the code

When compilation fails, the error is marked directly on the offending line:

• A bubble appears at the end of the line with the error message (multiple errors are staggered so they do not overlap)
• A squiggle is drawn at the error position (red = error / orange = warning / green = hint)
• The bottom panel switches to the Problems tab, listing every issue; tap one to jump to that line

Bubbles are part of the code: they scroll with it and scale with it, and their position depends only on code coordinates.

⚠ As soon as you touch the code, the previous round of errors is cleared — those line numbers have probably shifted, and leaving them floating over the code would only show you false information.

Status bar

One line at the bottom shows: encoding · read-only/edit · lines · size · caret position. At a glance you can see whether you can edit right now, and where the caret is. While zooming the font it also shows the font size for a few seconds, then hides itself again (it is not kept there permanently, so it does not take up room).

The icon at the far right opens / closes the bottom panel.