Der Screenshot zeigt, dass der Cursor im falschen Feld steht.

Because Screenshot is a masculine noun in standard German: der Screenshot.

In this sentence, der Screenshot is also the subject of the main clause:

• Der Screenshot zeigt, ...
• The screenshot shows ...

So der here is both:

• the normal nominative singular article for a masculine noun, and
• the marker that this noun is the subject.

In German, a clause introduced by dass must be separated from the main clause by a comma.

So the sentence is divided like this:

• Der Screenshot zeigt,
• dass der Cursor im falschen Feld steht.

This is standard German punctuation. English often does not require a comma before that, but German does before dass.

dass means that and introduces a subordinate clause.

So:

• Der Screenshot zeigt, dass ...
• The screenshot shows that ...

A very important grammar point is that a dass-clause sends the finite verb to the end:

• ..., dass der Cursor im falschen Feld steht.

That is one of the most common subordinate-clause patterns in German.

Because the part after dass is a subordinate clause, and in German subordinate clauses the conjugated verb normally goes to the end.

Compare:

• Main clause: Der Screenshot zeigt ...
• Subordinate clause: dass der Cursor im falschen Feld steht

If this were a main clause by itself, the verb would be earlier:

• Der Cursor steht im falschen Feld.

But after dass, it moves to the end:

• ..., dass der Cursor im falschen Feld steht.

Because der Cursor is the subject of that clause:

• dass der Cursor im falschen Feld steht
• that the cursor is in the wrong field

The cursor is the thing doing the standing / being positioned, so it is in the nominative case.

That is why it is:

• der Cursor (nominative)

not:

• den Cursor (accusative)

im is a contraction of in dem.

So:

• im falschen Feld = in dem falschen Feld

In English, that is usually just in the wrong field.

This contraction is very common in German:

• im Haus = in dem Haus
• im Büro = in dem Büro

Because Feld is in the dative case here, and the adjective must take the correct ending.

Here is the structure:

• in
  • location = usually dative
• dem Feld = dative singular
• with an adjective: dem falschen Feld

Since im = in dem, you get:

• im falschen Feld

Why dative? Because this sentence describes location, not movement:

• The cursor is in the wrong field → location

Compare:

• im falschen Feld = in the wrong field (location, dative)
• in das falsche Feld = into the wrong field (movement, accusative)

Yes, Feld literally means field, but in computer and form-related language it also means a field, box, or input field on a screen.

So in this sentence, im falschen Feld most naturally means something like:

• in the wrong field
• in the wrong input box
• in the wrong form field

The exact English wording depends on context, but field is usually the best match.

German often uses verbs like stehen, liegen, and sitzen to describe where something is located, where English often just uses is.

So:

• Der Cursor steht im falschen Feld.

literally looks like:

• The cursor stands in the wrong field.

But the natural English translation is:

• The cursor is in the wrong field.

This use of stehen suggests position or placement. In technical or visual contexts, it is very normal to say that a cursor steht somewhere on the screen.

The subordinate clause follows this pattern:

• dass
  • subject + other information + verb

So here:

• dass
• der Cursor
• im falschen Feld
• steht

This is a very useful model to remember for German subordinate clauses.

Yes. That would be a complete main clause meaning:

• The cursor is in the wrong field.

The full original sentence adds another main clause before it:

• Der Screenshot zeigt, dass der Cursor im falschen Feld steht.

So the original sentence is basically:

1. The screenshot shows
2. that the cursor is in the wrong field

The second part becomes a subordinate clause because it depends on zeigt.