Starting with 4Dv14, the query editor received an update. Due to this update there are some changes in performance with regards to the 'Filtering of commands and project methods in the formula editor' setting.
With this setting enabled all methods and commands are hidden from the formula editor. This is set as the default setting for security reasons to prevent ill intentions from abusing the query editor to run methods.
When this setting is disabled all methods are loaded onto the query editor. Before this setting would not have an effect on the simple query editor, however with the changes made this now has an impact on the query editor and can cause significant slow downs in databases with a large number of methods, even if the methods are small.
As such, for these reasons it is best to leave this setting as default to enabled and use the command SET ALLOWED METHODS to pass an array of methods accessible by the query editor limiting the amount of methods loaded and decreasing the overhead introduced by loading a large number of methods.