You mean, when you double click on a DXF file in the file browser, it opens with True View?
I assume you have installed True View recently. This may have modified the default application setting for DXF files.
You can reset or change it to LibreCAD, but that depends on your operating system.
Or you open LibreCAD first and the select File -> Open... to open the DXF file in LibreCAD.
Armin
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