Is a comma needed?

No, but again, thats only my opinion.

The comma is neccessary to avoid ambiguity, that is to avoid conveying or confusingly suggesting the meaning that she is no longer: [angry with you because you explained is such great detail]

Thanks, Contrex.

My meaning is that she is no longer angry with you. So does it mean a comma in not required? Thanks again.

Yes, I had gathered your meaning! The comma is necessary to separate two clauses.

Maybe my square brackets device was not sufficiently clear. Sorry!

Without the comma, the suggestion is that she is no longer angry with the other person, the reason for her previous anger being the fact that they explained in such (excessively?) great detail.

With the comma, the suggestion is that she is no longer angry with the other person, the reason for her anger having abated being the fact that they explained in such (sufficiently?) great detail.

Hi Contrex

Without the comma, the suggestion is that she is no longer angry with the other person, the reason for her previous anger being the fact that they explained in such (excessively?) great detail.

With the comma, the suggestion is that she is no longer angry with the other person, the reason for her anger having abated being the fact that they explained in such (mollifyingly?) great detail.

I'm sorry to have to ask you again. What do 'excessively' and 'mollifyingly' mean?

Many thanks.

ex·cessive·ly adv.
ex·cessive·ness n.

Synonyms: excessive, exorbitant, extravagant, immoderate, inordinate, extreme, unreasonable

These adjectives mean exceeding a normal, usual, reasonable, or proper limit. Excessive describes a quantity, amount, or degree that is more than what is justifiable, tolerable, or desirable: excessive drinking.

mollifyingly adv

from

mollify verb

To ease the anger or agitation of: appease, assuage, calm (down), conciliate, dulcify, gentle, pacify, placate, propitiate, soften, soothe, sweeten. Idioms: pour oil on troubled water.

My heartfelt thanks, Contrex, for painstakingly explaining to me what I was not sure about.

Best regards.