Script Debug Window

Composer Desktop ships a dedicated Script Debug Window for iterating on scripts without leaving the application — a compact, always-on-top floating panel that surfaces the script engine's live state and recent log activity in one view. Open it from the application menu: Script Engine → Open Script Debug Window….

What the window shows

The window is split into three regions, top to bottom:

1. Engine status panel. Live readouts for the running script:

Engine status — current ScriptEngineStatus (Disabled / Running / Updated / Error / Stopped / NotInitialized).
Script — the script file currently loaded by the project.
Execution time — how long the most recent OnRenderFrame invocation took. A useful budget gauge — anything close to the per-invocation timeout will eventually trip the script-engine timeout error described in Errors and debugging.
Frame counter — how many frames the script has seen since it last started. Increments only while Running.
Last error — when the engine is in the Error state, the error message renders in red. Otherwise hidden.

A row of one-click buttons sits below the readouts:

Reload — equivalent to ReloadScriptCommand (re-reads the script file and restarts the engine).
Edit — opens the script in the in-Desktop script editor.
Start / Stop — drives the engine's lifecycle directly without going through the application menu.
Clear log — wipes the Script-Engine log buffer and the visible list (does NOT clear the Composer system log).
Font size — Small (default) / Medium / Large dropdown for the log list, useful when projecting on a producer screen.

Filtering log severity

Six checkboxes drive what's visible in the log list:

Filter	Severity
Show Fatal errors	`Fatal`
Show Errors	`Error`
Show Warnings	`Warning`
Show Info events	`Information`
Show Debug events	`Debug`
Show Trace events	`Verbose`

Log list

Right-click any entry (or a multi-select) to Copy the rendered text to the clipboard — handy for pasting into a bug report or an issue ticket.

When to use it vs the main log window

Script Debug Window — script-engine output only. Use while iterating on a script to see your own Log.Info / Log.Error calls and engine timing in real time.
Log window (in the Operations manual) — every Composer subsystem (capture, decoders, network, render). Use when an issue might span the script and something else (an input that disconnected, a target that throttled).

The Script Debug Window only displays log entries written through the Script Engine logger — not output from inputs, targets, operators, or the runtime itself. For those, the main Log window is the right tool.