Hi Gabriel,
If you're dragging and dropping from a yellow Search Area folder, then you can configure the order that DataPlugins are tried for a TXT file. Choose the NAVIGATOR menu "Settings >> My DataFinder >> Configure..." to pop up the "Configure My DataFinder" dialog. Then choose the 3rd "File Extensions" tab and click on the *.txt file extension in the top left part of that dialog. Finally move the available DataPlugin names up and down with the blue up and down arrow icons in the top right of the dialog. The DataPlugin name at the top of the list will be tried first.
If instead you're dragging and dropping from a gray non-Search Area folder, then your options are limited. You can definitely right-click on the file and choose the context menu "Open with..." and then select the desired DataPlugin to use in the import, but this DataPlugin selection will not "stick", it will just be used to import the data file you right-clicked on. You might try unregistering all the TXT DataPlugins, then re-registering the one you want to be the default DataPlugin first and re-registering the other DataPlugins afterwards. I think the first DataPlugin that was registered is the default DataPlugin for that file extension.
Ask if you have further questions,
Brad Turpin
DIAdem Product Support Engineer
National Instruments
