A final step in making sure that the import into LEXUS will cause problems is to be aware of the possibility of double-defining markers. As in Toolbox markers are defined under other markers, it happens often that certain data categories seem to appear consistently in more than one place in the data file. Most often this is the case for . In the MDF file, it is defined under . However, except for appearing under the marker, it will also be found throughout your lexicon also under . The structure is actually in each case the same: appears under which is under . In those cases, where it is found under in the data file, the marker (which is in the structure between and ) is simply not expressed explicitly. For Toolbox, as we already know, this is not a problem.
In this case, however, LEXUS will have to create an empty group between every and . Importantly, in this place is very consistent throughout lexica and it is desirable to have it there. To solve this problem, LEXUS allows to double define markers manually by simply copying the definition of in the .typ file and changing in the copy of that definition the node under which it is defined from to . In that way, in the structure file we have two definitions of the marker: one under and another under . This double definition will not be recognized by Toolbox, but LEXUS will be able to cope with it. There is no limitation as to the number of double-defined elements in your .typ file but the general rule is: the fewer the better.
Often, there are more than three markers that you would like to double-define. The only solution here is to first order them in a hierarchy and to double define only the very top marker of that hierarchy. The markers that are defined under it will automatically appear under the double-defined markers, both under and for instance.