When background geoprocessing is disabled and any GP tool is run from Windows > Search > Search Window Open Up > Search, ArcMap hides under the other window and becomes inactive when the tool completes. This occurs when ArcMap is sitting on top of another application (e.g., MS IE or Mozilla) and the Tools toolbar is docked somewhere in the ArcMap interface.
retested with 10.1 build 2783, 30Jun11 - canNot repro.
対処法
Select the geoprocessing tool from ArcToolbox.STEPS:1.Launch ArcMap and add any layer.2.Go to Geoprocessing menu > Geoprocessing Options and disable background geoprocessing.3.Go to Geoprocessing menu > Arctoolbox > Select any tool > perform operation.