Hi Mourice,
Can you please apply latest Patch Level of SAP GUI for Windows 7.40 and latest Patch Level for
BI 7.0 ADDON FOR SAP GUI 7.40 and check whether it helps you.
Also, please refer the following SAP Note:
147519 - Maintenance strategy / deadlines for SAP GUI
And, please refer the following SAP Note and check whether it helps you:
1968442 - Leaves under expanded hierarchy nodes vanished when expanding other hierarchy nodes
Thanks & Regards,
Sapna