"While Melania stayed in New York, Ivanka continued to establish herself in the West Wing, notorious for its cramped and limited working spaces."

"According to several people, she was eyeing real estate in the East Wing as well, the domain of the first lady. Among other proposals, Ivanka suggested renaming the 'First Lady’s Office' the 'First Family Office.' Melania did not allow that to happen. It was tradition, and she was not going to let her stepdaughter change it. Ivanka’s office remained in the West Wing. Melania’s delay in moving from New York initially put her at a disadvantage. Even some of the staff positions and budgets that would have been available to support the first lady’s office were gone, diverted to support those in the West Wing, including Ivanka.... With Melania away, Ivanka used the private theater, with its plush red seats, and enjoyed other White House perks. Some said she treated the private residence as if it were her own home. Melania did not like it. When she and Barron finally moved in, she put an end to the 'revolving door' by enforcing firm boundaries.... People working in the West Wing say they have heard Trump criticize Don Jr. and Eric and even Ivanka for doing or saying something that the president thought was not helpful, but none could recall hearing him say anything negative about Melania.... More than a dozen past or current White House officials interviewed attributed Melania’s influence to the fact that Trump believed that just about everyone else had an agenda, except Melania. He believed she had no ulterior motive and just wanted him to succeed...."

From "How Melania Trump blocked Ivanka Trump from encroaching on her domain" by Mary Jordan (adapted from the book, "The Art of Her Deal: The Untold Story of Melania Trump")(WaPo).