Take a look at the taskbar at the very bottom of the screen (under the colour swatches). It'll tell you there if you're in a group. See screenshot attached.
EDIT: I should add, there's also an indication when you're inside a group where instead of showing the layer name, the indicator changes to the group name. See second screenshot.
Beginners' Questions Visual indicator that you're inside a group
Inkscape.org
As there are times you don't realize it when drawing, it would be nice to provide some visual indicator that you're inside a group.
Maybe a frame around the drawing area...
Take a look at the taskbar at the very bottom of the screen (under the colour swatches). It'll tell you there if you're in a group. See screenshot attached.
EDIT: I should add, there's also an indication when you're inside a group where instead of showing the layer name, the indicator changes to the group name. See second screenshot.