Getting an extra rest where not expected

Hi,

just started with Musescore. When working with voices I get a weird problem.

I have 4/4 signature and in measure 8 I entered the right notes to fill a measure for all 4 voices.
Still a half rest appears for voice 1 for no obvious reason.

Have tried a lot of things to no avail.

I'll attach the file. Please point me to my error.

Thx very much,
ArievW