Wenn der Cursor an der falschen Stelle steht, schreibe ich oft in die falsche Zeile.

Because wenn introduces a subordinate clause. In German subordinate clauses, the conjugated verb normally goes to the end.

So:

• Wenn der Cursor an der falschen Stelle steht
• literally: When/if the cursor in the wrong place is

This is one of the most important German word-order patterns to learn:

• Ich schreibe ... = normal main clause
• ..., wenn ich schreibe = subordinate clause, so the verb moves to the end

When a subordinate clause comes first, the main clause still follows the normal German rule that the verb must be in position 2.

Here, the whole wenn clause takes position 1:

• Wenn der Cursor an der falschen Stelle steht, = position 1
• schreibe = position 2
• ich comes after the verb

So German says:

• Wenn ..., schreibe ich ...

not

• Wenn ..., ich schreibe ...

This is often called inversion in beginner explanations.

It can mean if, when, or whenever, depending on context.

In this sentence, wenn suggests a repeated situation or a general condition:

• Wenn der Cursor an der falschen Stelle steht, schreibe ich oft in die falsche Zeile.
• When/If the cursor is in the wrong place, I often write in the wrong line.

A useful guideline:

• wenn = if/when for present or future situations, repeated events, or conditions
• als = when for a single event in the past

So here wenn is the correct choice.

Because this describes location, not movement.

The preposition an can take:

• dative for location: where?
• accusative for direction: where to?

Here the cursor is already located somewhere:

• Der Cursor steht an der falschen Stelle.
• The cursor is at the wrong place/position.

So German uses dative:

• an der falschen Stelle

If there were movement toward that place, you would use accusative:

• Ich setze den Cursor an die falsche Stelle.
• I place the cursor in the wrong position.

This is a very common learner question, because in is also a two-way preposition.

Here, in die falsche Zeile schreiben is idiomatic German when you mean writing/typing into a line, field, or box. German often treats this as writing something into a target space, so accusative is natural.

• in die falsche Zeile schreiben = write into the wrong line

By contrast, in der falschen Zeile would sound more like describing where something is located:

• Der Text steht in der falschen Zeile.
• The text is in the wrong line.

So in your sentence, die fits the idea of putting text into that line.

Because adjective endings in German change according to case, gender, and article.

Here you have:

• an der falschen Stelle

  • Stelle is feminine
  • der here is dative feminine
  • so the adjective takes -en → falschen

• in die falsche Zeile

  • Zeile is feminine
  • die here is accusative feminine
  • so the adjective takes -e → falsche

So the difference is caused by case, not by the meaning of falsch.

German often uses stehen for things that are positioned somewhere on a screen, page, or surface.

So:

• Der Cursor steht an der falschen Stelle.
• literally: The cursor stands in the wrong place

This sounds normal in German. English usually prefers is in this kind of sentence, but German often uses a more specific position verb such as:

• stehen = stand
• liegen = lie
• sitzen = sit

So this is normal idiomatic German, not strange wording.

They are related, but not the same.

• Stelle = place, spot, position

  • here: the cursor’s exact position

• Zeile = line

  • here: a line of text

So the sentence means roughly:

• the cursor is in the wrong spot
• and as a result, I write in the wrong line

That distinction is important.

Yes, adverbs like oft can move, but their position changes the rhythm or emphasis.

In your sentence:

• ..., schreibe ich oft in die falsche Zeile.

This is a very natural position. It means:

• I often write in the wrong line.

You may also hear:

• ..., schreibe ich in die falsche Zeile oft.
  This is much less natural here.
• ..., oft schreibe ich in die falsche Zeile.
  Possible, but now oft is more strongly emphasized.

So the given word order is the most neutral and natural one.

Not necessarily. In German, schreiben can be used quite broadly for both writing by hand and writing/typing text.

So with computers, Germans very often still say:

• Ich schreibe eine E-Mail.
• Ich schreibe in die falsche Zeile.

If you want to emphasize the physical act of typing on a keyboard, you could use tippen:

• ..., tippe ich oft in die falsche Zeile.

But schreibe is completely natural and often more general.

Yes, you could say an der falschen Position, and it would be understandable.

But an der falschen Stelle is often more idiomatic and more common in everyday German for this kind of context.

Compare:

• an der falschen Stelle = very natural, everyday
• an der falschen Position = a bit more technical or formal

So the original sentence sounds more natural in normal usage.

Because all nouns are capitalized in German, not just proper names.

So in this sentence:

• der Cursor
• die Stelle
• die Zeile

all begin with capital letters because they are nouns.

This is one of the easiest visual clues for spotting nouns in German.