several instances, forward show and path

[Hofknecht]

when using options -> Advanced:

then we do not kill other instance. (discuss kill other instance behavior here #352)

there is the expectation that e.g. through a link to the stm with e.g. arguments can set it to change the root folder. E.g. one could build a 'go to folder 2' link which sets the root folder to folder 2 and a 'go back to folder 1' which sets the root folder to 'folder 1'. However, currently if you give the path as an argument, then a new instance is started. It would be desirable if only the first instance gave the path to the second, but the communication takes too long, there are lot of ways like also described here:
https://stackoverflow.com/questions/9701757/when-to-use-pipes-vs-when-to-use-shared-memory

or there is also the expectation that like windows toolbar you can have several menus next to each other. Therefore we made a
for others very confusing memory picture, if we come back to the topic again