merge vector layers

[globso]

im trying to merge a couple of vector layers in designer. i have made a couple of lines and now i want to round the edges. i thought in all my naiveness that i could just merge all these layers and then use the "round corner" tool. but as i have seen on the web there seem to be no way of merging vector layers, you can only group them, but that does not help when im trying to use the rounding tool. 
 is it just affinity that works this way, or is it impossible to merge layers in all vector software?

[globso]

i just found an answer that works for me, i dont know if its the right way, but i can make a bolean action on every part and fuse them together that way. it would off course  be easier if the possibility to highlight every layer you want to merge, and then just do it. but i guess i have to merge part by part with the bolean

[telemax]

Hi,

RMB, Geometry > Merge Curves
or 
Main menu > Layer > Geometry > Merge Curves

Tip: If the "Corner Tool" has no effect on some vertices, select all or only the problematic vertices and apply the "Convert to Sharp" command to them.

[globso]

i love you! i got as far as the last corner to round up, but that did not work for some reason. i went here and you had already in som mystic pshycic way answered that exact question before i hade asked it...scary  

[telemax]

This is a common problem. After boolean operations, some nodes ignore the "Corner Tool". I assume that they get bezier control knobs that end up inside that node (in the same coordinates as the node, so you can't even see them).