Entering the Modify mode to change a feature's geometry can be done by either double-clicking on a feature, or by clicking the edit vertices button when a feature is selected. As the feature enters Modify mode, ArcMap begins a redraw so that it can change the symbology used to represent the features geometry. This is not often apparent because most data is fast to redraw, however with complex data sets the redraw can take a long time. If this behavior negatively impacts your work, follow the steps in this article to change ArcMap so that it will not redraw when a feature is loaded into Modify mode.
At ArcMap 10.1, to make editing vertices easier, we added transparency to the symbols of the feature being edited. This causes a redraw around the feature which is not desirable for complex datasets. The default behavior is helpful in most cases, so instead of changing it we have added a registry key to help users who cannot work with the redraw.
Warning: The instructions below include making changes to essential parts of your operating system. It is recommended that you backup your operating system and files, including the registry, before proceeding. Consult a qualified computer systems professional, if necessary. Esri cannot guarantee results from incorrect modifications while following these instructions. Therefore, use caution and proceed at your own risk.
Add the following registry key for each user:
ArcMap 10.6 and ArcMap 10.2.1 with the Utilities and Telecom Update 8 reads the registry key on startup and changes the behavior accordingly.