I tried to edit the details of an entry in Manage Search Engines by clicking the text under one (or any) of the 4 columns and then altering the text. After pressing Done and reopening the window I found that the edited part had reverted back to the original text. For example, if I change the Keyword from X to Y and then reopen MSE the X is still there.
The edited part should remain after pressing Done.
v0.99.134-beta, OS X 15.5
Sequoia (15)