In Database Explorer, two tables cannot be dropped if both have foreign key contraints referencing each other.

This is relevant for some one-to-one relationships.

Testcase:

CREATE TABLE TABLE_1 (ID INTEGER NOT NULL, TABLE_2_ID INTEGER NOT NULL, PRIMARY KEY (ID));
CREATE TABLE TABLE_2 (ID INTEGER NOT NULL, TABLE_1_ID INTEGER NOT NULL, PRIMARY KEY (ID));
ALTER TABLE TABLE_1 ADD CONSTRAINT FK_TABLE_1_TABLE_2_ID FOREIGN KEY (TABLE_2_ID) REFERENCES TABLE_2 (ID);
ALTER TABLE TABLE_2 ADD CONSTRAINT FK_TABLE_2_TABLE_1_ID FOREIGN KEY (TABLE_1_ID) REFERENCES TABLE_1 (ID);

When trying to drop the tables in Database Explorer by right click|delete, the error is:
Unable to execute command:
drop table "APP"."TABLE_2"
Operation 'DROP CONSTRAINT' cannot be performed on object 'SQL100704071938090' because CONSTRAINT
'FK_TABLE_1_TABLE_2_ID' is dependent on that object.

This looks like a bug because Database Explorer seems to try to drop constraints two times.

This worked as expected:

ALTER TABLE TABLE_1 DROP CONSTRAINT FK_TABLE_1_TABLE_2_ID;
ALTER TABLE TABLE_2 DROP CONSTRAINT FK_TABLE_2_TABLE_1_ID;
DROP TABLE TABLE_1;
DROP TABLE TABLE_2;