Large designs that contain numerous, childless GUs and few work locations, can experience performance problems upon opening. For small designs, this is not normally observed as an issue. However, for large designs, a large number of childless-GUs with few work locations can cause slowness in open times. This behavior is caused by issue CLS-60009 and has been reported in version 10.2.1.
This issue stems from designs having a large number of childless GUs. When a design is opened, merging occurs between the Design Tree XML and the WFM XML from the PX tables. For childless GUs, an iterative check is performed to confirm their position within the tree.
For more information on the hierarchy of GUs and CUs within a design, please refer to the following topic: http://resources.arcfmsolution.com/10.2.1c/DesktopUsing/DesignTab.html
The reported issue CLS-60009 has been resolved in 10.2.1c. If running an earlier version of Designer, a workaround for this issue has been identified to improve performance. Increasing the number of work locations within the design and dividing the childless GUs among the work locations will help to improve a large design’s open time. This workaround divides the iterative checking process into smaller lists when confirming GU positioning within the tree.