[ESS] R Error splits code frame

[Johannes Aengenheyster]

Dear all, 
For some months now, I basically have the exact same problem as here: https://grokbase.com/t/r/ess-help/1319gq8w1m/ess-error-message-in-r-now-splitting-frame. I have one frame with an R process, and one (or more) frames with R code. As soon as R produces an error, the code frame gets split in half and the R process is shown in the new window. Since I already have a frame with a R process, I do not want this to happen. Anybody have an idea what to do? (I'm using emacs 26.1.50 on ubuntu 16.04 with ESS 18.10.3) Thanks in advance!