When clicking on InstancedStaticMeshComponent with many elements, Editor memory usage increases and editor freezes until the operation is finished. The wait and memory usage get much worse when using Japanese IME.
0. (Turn on Google Japanese Input or Microsoft IME)
1. Open the attached scene
2. Open Task Manager to check UE4 memory usage
3. Click on NewBlueprint2, then click its InstancedStaticMesh component in Details
4. Do the same as other two blueprints
5. When there are more elements, memory usage will be worse, and Editor will freeze for a while
There's no existing public thread on this issue, so head over to Questions & Answers just mention UE-48100 in the post.