Деликатный режим уже выбран.

Because режим is the grammatical subject of the sentence.

In Деликатный режим уже выбран, the sentence is about the delicate mode. The word выбран agrees with режим, so режим stays in the nominative singular.

• режим = nominative singular masculine
• выбран = masculine singular short passive participle

So the structure is basically:

• Деликатный режим = the delicate mode
• уже выбран = is already selected / has already been selected

Because деликатный is an adjective modifying режим, and it must agree with it in gender, number, and case.

Since режим is:

• masculine
• singular
• nominative

the adjective must also be:

• masculine
• singular
• nominative

So:

• деликатный режим = correct
• деликатного режима would be genitive, meaning something like of the delicate mode

Выбран is the short-form passive participle of the verb выбрать (to choose/select).

It agrees with режим:

• masculine singular: выбран
• feminine singular: выбрана
• neuter singular: выбрано
• plural: выбраны

In this sentence, it means that the mode is in the state of having already been selected.

So выбран is not a normal past-tense verb like выбрал (chose). It is specifically a passive form: selected.

Because выбрал means chose and is an active past-tense verb. It would require a subject who did the choosing.

For example:

• Он выбрал деликатный режим. = He chose the delicate mode.

But in your sentence, the focus is not on who selected it. The focus is on the result:

• Деликатный режим уже выбран. = The delicate mode has already been selected.

So:

• выбрал = active, someone chose it
• выбран = passive, it has been chosen

Russian normally does not use a present-tense form of to be in sentences like this.

So where English says:

• The delicate mode is already selected
• The delicate mode has already been selected

Russian can simply say:

• Деликатный режим уже выбран.

The idea of is is understood. Russian often leaves it out in the present tense.

That is why the sentence can sound very compact in Russian.

Уже means already.

In this sentence, it modifies выбран, so the meaning is:

• already selected
• has already been selected

The position Деликатный режим уже выбран is very natural and neutral.

You may also see уже in other positions, but moving it can slightly change the emphasis. For example:

• Уже выбран деликатный режим. = emphasis a bit more on already
• Деликатный режим выбран уже. = possible, but less neutral in many contexts

For learners, the safest default here is the original word order.

It can correspond to either in English, depending on context.

Russian short passive participles often describe a resulting state. So:

• режим выбран can mean the mode is selected
• or the mode has been selected

In many practical contexts, English naturally uses the present perfect:

• has already been selected

because уже strongly suggests that the action happened before now and the result is relevant now.

Yes, but it means something a little different.

• Деликатный режим уже выбран. = The delicate mode is already selected / has already been selected.
• Деликатный режим был выбран. = The delicate mode was selected.

Adding был makes it clearly past. Without был, the sentence usually describes the current state/result.

So if you are talking about what is true now, the original sentence is better.

Because выбран is not a full adjective here. It is a short-form participle.

Compare:

• full form: выбранный = selected
• short form: выбран = selected (in predicate position)

Russian often uses the short form after the noun, especially in statements like this:

• Режим выбран.
• Заказ готов.
• Дверь закрыта.

This is very common when describing a state or result.

Not by itself.

Деликатный режим уже выбран does not say who did it. The agent is omitted because it is either unknown, obvious, or unimportant.

If you want to mention who did it, Russian can add that information separately, for example:

• Деликатный режим уже выбран пользователем. = The delicate mode has already been selected by the user.

But in the original sentence, the important information is simply the result: the mode is already selected.

Yes, Russian word order is fairly flexible, but different orders can sound more or less natural and can shift emphasis.

The most neutral version is:

• Деликатный режим уже выбран.

Other possible orders include:

• Уже выбран деликатный режим.
• Деликатный режим выбран уже.

These are not identical in tone. The original sentence is the best default for a learner because it sounds straightforward and natural, especially in interface or status-message style language.

Yes, especially in technical or appliance contexts, such as washing machines, dishwashers, or other devices with settings.

Here деликатный means something like delicate/gentle, and режим means mode/setting/program mode depending on context.

So the phrase is natural in practical usage, especially in menus, labels, and device messages.