I just started using SumatraPDF and I like it very mich, but there is one thing that annoys me:
when SumatraPDF has the window focus (I clicked inside) and when I then move the curser outside to another window and scroll I expect the window where the cursor is to scroll, even if I havn’t clicked inside to activate it, but instead the PDF srolls.
I am using Win10 and in the settings I have enabled this setting to scroll inactive windows.
In win10 my experience is the default is to scroll ANY window when hovering but it may vary from version to version.
If you keep windows to scroll inactive windows then SumatraPDF will be affected same as any other. however that is a windows setting of your choice. Hovering over SumatraPDF behaviour should not be different than say hovering over this window in Internet Explorer, etc.
Actually just noticed it is internet explorer that behaves oddly when switch is OFF not the same as others . Best to compare Sumatra action versus Windows Explorer or Notepad behaviour.
I just googled around a little and found out that it might be a driver related problem. Other programs behaved oddly too, so I tried my luck and went to device manager and told it to use the last drivers (for my synaptics touchpad) and now it seems to work again