Namespace disappear

[griabcrh]

as shown above, extend flowable,

[philippfromme]

Lovely screenshots. Mind explaining what your question is?

[griabcrh]

xmlns:flowable="http://flowable.org/bpmn"

question: flowable namespace disappear

When importing , the flowable namespace exists, but on export, the flowable namespace disappears

[philippfromme]

Does the diagram you export contain any elements that use the flowable namespace?