Question: I lost my dimension "snap"/associativitydrawing property that represents the linking of drawing objects to model objects so that the former are updated according to changes made to the latter in the modeling mode
In Tekla Structures, associativity only relates to one type of drawing objects, namely associative objects. These can be building objects and associative annotation objects.
In Tekla Structures, the term associativity has traditionally been used when referring to the linking of drawing objects to model objects. In other modeling contexts, however, the term associativity may refer to any kind of linking between model objects or parts of a model by using dependencies.
Normally they are like this, when dimension or mark or similar selected.
Now they are like this. (no "nails" / snap symbols).
Answer: Check that you have not hidden the symbols by pressing the keyboard shortcut Shift+A.