open-vm-tools-desktop passed drag_and_drop from Host(RHEL) to Guest(RHEL) but failed from Guest to Host

From VMware VMware Knowledge Base , open-vm-tools-desktop supports files drag_and_drop between Host and Guest. But partial success.

1. Host bare metal machine installs a RHEL7.5 and installs a Linux VMware Workstation Pro 15.0.4.

2. Create a VM with RHEL7.6 in this VMware Workstaion, enable its "drag and drop" and "copy and paste".

3. Boot this VM successfully.

4. Drag a file from a Host folder to Guest VM desktop, it works well.

5. Plan to drag a file from a Guest folder to Host desktop, but it fails.

6. From /tmp/VMwareDnD in Host, has built the fCQf65 folder, it is link to /home/tester1/.cache/vmware/drag_and_drop/fCQf65. It is null.

7. NO idea to find somewhere stores useful log.

Thanks.