The frustrating part is not knowing why this happens. I can't tell whether VectorStyler produced a mathematically valid result based on the geometry, encountered a condition it couldn't process correctly, or experienced an actual bug.

I usually end up trying several different fixes until something works. This becomes a trial-and-error process without understanding the cause.

Here is a video showing how there was an unexpected result at first and part of the vectors on screen disappeared.

Would it be technically feasible to introduce an optional diagnostic command that analyzes shapes both before and after an operation?

Before an operation

I could select one or more objects and run a command such as "Shape Diagnostics" to identify potential problems before applying Merge, Unite, Expand, or another operation.

For example, it could check for:

Open paths or self-intersections

Duplicate or overlapping paths

Multiple fills or strokes that might affect the operation

Compound paths or complex appearances

Other geometric conditions that could produce unexpected results

Ideally, VectorStyler would highlight the affected objects or paths, explain the potential issue, and suggest a correction.

After an operation

If an operation produces an unexpected result, I could run the diagnostic command to investigate what happened.

Ideally, it could distinguish between:

A mathematically valid result that may not match the user's expectations

A known geometry or appearance condition that affected the result

An operation that encountered a processing error

It would be particularly useful if VectorStyler could identify which objects or regions were removed or altered and explain the likely reason.

An existing example from the VectorStyler forum

A good example of why this feature would be useful is the discussion:

Merge operation deletes the object underneath

In that report, the Merge operation unexpectedly deleted the lower object instead of producing the expected result.

The developer confirmed that the behavior was a bug and later identified the cause: the blue object contained two blue fills, which the operation was not handling correctly.

The suggested workaround was to remove one of the fills in the Appearance panel before applying Merge.

This illustrates exactly the kind of problem I'm describing.

Without the developer's explanation, a user might spend considerable time modifying paths, changing object order, or experimenting with other settings without realizing that the additional fill was responsible.

An optional diagnostic command that could identify a condition like this would make troubleshooting considerably easier.

Optional rather than automatic

I would prefer diagnostics to be available on demand rather than having warnings interrupt normal operations.

I'm not suggesting that VectorStyler should predict the user's intended result. I'm asking whether the application could expose information about the geometry and processing conditions that influence the outcome.

The goal is to eliminate the guesswork. Instead of repeatedly experimenting with different fixes, users could identify potential problems beforehand or investigate unexpected results afterward.

Even a basic diagnostic report that identifies problematic objects and suggests possible corrections would be valuable.

Is this something VectorStyler's current geometry engine could realistically support?