THE SOLUTION:
After multiple searches, I found one path to be wrong (it was my first intution).
Download the IDE source code (zip) from
https://github.com/fantaisie-software/purebasic
Open purebasic-devel\PureBasicIDE\Explorer.pb
Line 168: ExplorerListGadget(#GADGET_Explorer, 0, 0, 0, 0, ExplorerPath$+StringField(ExplorerPatternStrings$, ExplorerPattern+1, "|"), #PB_Explorer_MultiSelect | #PB_Explorer_AutoSort | #PB_Explorer_FullRowSelect | ExtraFlags)
After a debug session, i found that the
ExplorerPath$ variable was wrong.
Maybe because I have several installations of PB, on several discs!
The solution was to open the %AppData/PureBasic/PureBasic.prefs file, go to the "Explorer" section and change the "Path" key, until it worked.
M.