>matter is user thinks is better a dblclick on the related field to show the next form instead moving to the toolbar and pressing clic, what do you think?
OK, that is no problem. Another alternative is to have an extra button, for instance with a Caption of "...", like the one you see in the "browse" button next to the place where you type a directory. But I don't see any problem with double-clickin on the field.
The problem is in emulating a double-click on the toolbar button. When double-clicking the field, you should only invoke a single click (Click() event) on the Toolbar button.
Difference in opinions hath cost many millions of lives: for instance, whether flesh be bread, or bread be flesh; whether whistling be a vice or a virtue; whether it be better to kiss a post, or throw it into the fire... (from Gulliver's Travels)