Product: Aqua Data Studio
Version: 17.0.0-dev-68
Build #: 44582
Build Date: 2015-Jul-01 06:18:01 PM

Operating Environment: Linux (3.13.0-32-generic, amd64) / UTF-8 / en / IN / Oracle Corporation 1.8.0_40-b26
Memory: Max=704,643,072;  Total=281,542,656;  Free=107,384,512;  CPUs=8

Steps to reproduce the issue :
1) Connect to PostgreSQL 9.4.
2) Expand PostgreSQL Server node
3) Expand Security Tree node, Right click on 'Groups' and Select "Create Group" option.
4) Create Group window opens, in General tab, Enter Group name and Select some Users in 'User Members' Pane.
5) Now switch to 'Database Access' tab, In Database Access Pane assign create privilege to some databases and from 'Tablespace Privileges' Pane assign privileges to some Tablespaces.
6) Now switch to 'Preview SQL' tab, In this Create Group is generated with Grant script on Databases and Tablespaces.

Script in 'Preview SQL' tab :
CREATE GROUP "Test_Group"
GO
GRANT CREATE ON DATABASE "test_project" TO GROUP "Test_Group"
GO
GRANT CREATE ON DATABASE "Test_DB" TO GROUP "Test_Group"
GO
GRANT CREATE ON TABLESPACE "pg_default" TO GROUP "Test_Group"
GO
GRANT CREATE ON TABLESPACE "test" TO GROUP "Test_Group"
GO
ALTER GROUP "Test_Group" ADD USER "nishtha"
GO
ALTER GROUP "Test_Group" ADD USER "postgres"
GO

7) Now click on Create Button, Group created successfully.
8) Now Right click on created group and select "Script Object to Window As" -> "CREATE" option.

Create Group script is generated but grant script is not displayed for Tablespaces.
It only displays Grant script for Databases.

Generated Script :

CREATE GROUP "Test_Group" WITH SYSID 18104
GO
GRANT CREATE ON DATABASE "test_project" TO GROUP "Test_Group"
GO
GRANT CREATE ON DATABASE "Test_DB" TO GROUP "Test_Group"
GO
ALTER GROUP "Test_Group" ADD USER "postgres"
GO
ALTER GROUP "Test_Group" ADD USER "nishtha"
GO