It's a known bug, i think he's already fixed it on the next build, for now just press G to go into top view, if scroll doesn't work, come out of top view and press G again and it should fix it, it's worked every time for me.
Quote: "
V1.141 now available as a Public Preview from Steam, includes the following fixes:
* Waypoint nodes no longer being edited when in EBE mode
* Fixed crash bug caused when you place an entity then immdiately use UNDO
* Fixed issue of mouse wheel disabling when leave EBE for first time each session
* When EXTRACT performed, mouse now centers on Widget position, less chance for mess
* IDE now expands the Fixtures entitybank folder for one less click to get a door
* Changed the Fixtured subfolders to capital first letter to match entitybank
* Modified loading EBE from local entity library to create new instance in level
* NOTE: Above allows modifications to be retained on save/reload and protect saved EBE
* Now when delete EBE file from saved EBE, it turns into regular (uneditable) entity
* Corrected static_basic.fx to re-include the SpecularOverride constant (lightmap shader)
* Fixed lightmapper to no longer force meshes to flat-shading (now keeps smoothing groups)
* Added slider to control Lens Flare intensity, and adapted post process shader to suit
* When you hold down CTRL while EBE painting, it axis locks the initial direction
* Added slider to control Surface Sun Intensity (defeats sun influence for indoor scenes)
* Adjusted main surface and shadow shading to use Sun Surface Factor
* NOTE: The Surface Sun Intensity slider is experimental but can control DOT3 lighting
"
i5, NV960 2GB, 16GB memory, 2x 2TB Hybrid, Win10.