IDE compiles wrong sketch

my IDE 1.6.9 is installed on a Win10 tablet.
After some tests with sketch-1 I opened a second one, sketch-2.

The active Window on the desktop is sketch-2. When I press the "upload" button, I get error messages about sketch-1.

In file included from sketch\sketch-1\epd.cpp:15:0 ... and so on

Even after moving the folder with sketch-1 out of the folder with all my sketches the IDE always wants to compile sketch-1.

On my Win7 PC I never saw such a strange behaviour. Anywhere the IDE remembers sketch-1 and does not change to sketch-2.
Does anybody know how I can get compiled sketch-2?