The board member who resigned:
Berlin, who hadn’t seen the exhibit before resigning, said it didn’t acknowledge the estimated 850,000 Jewish people who were forced to flee Arab countries in the years following the establishment of Israel.
Further down the article:
The museum invited media to view the exhibit Friday.
...
A timeline references displacements on both sides: “Before, during and after the war, hundreds of thousands of people became refugees. These included Palestinian Arabs as well as Jews from surrounding countries.”