RESOLUTION 1:
This needs to be a two-step process where you add the new columns first to a table, and then do a Rebuild Table as the 2nd step.
First, go to Schema Browser | Tables Tab | highlight the table you want to modify.
Basically, you can run your own script to add the new columns to a table OR use the “Alter selected Table” icon in the Schema Browser Window if you want to use Toad’s GUI feature.
After adding the new columns, click on the “Rebuild this Table” icon in the Schema Browser Window.
Go to the Columns Tab and from there you can arrange the Columns by dragging them up or down. When you are done arranging the columns, click on the Script Tab, which will show you what Toad will run in the background.
Fully examine the script and ensure the changes (and how Toad will accomplish the task) is fine with you. Toad will ensure that the Table constraints, indexes, etc. are preserved. If all looks good for you, click on the green “Play” icon on the top.
NOTE: Please read the Comments in the Script for more details and warnings.
RESOLUTION 2:
The DBMS Redefinition Wizard allows users to reorder the Oracle table columns. The DBMS Redefinition Wizard can be found by selecting Database | Optimize in Toad's menu bar.