PL/SQL Developer by allroundautomations has a very nice feature. When you hold down Ctrl, any object or variable inside plsql or sql code is highlighted, as soon as you move the mouse over it. When you click the highlighted text, you'll jump the declaration of the (variable, type, function ...). If you click on a table, the table will be opened in schema browser. It is possible to use left and right mouse button. Both act the same, except for packages and types. If the target lies within a package or type, left click will jump to the declaration (specification) and right click will jump the the definition (body).
Would be nice, if something similar could be implemented in TOra