the cursor miscalculates columns

[origedit]

1. set tabs to be bigger than 1 space
2. write some code
3. enter an indented line
4. jump up or down from it to a differetly indented line
5. the cursor will be off by the difference in the amount of tabs

the functions lineUp and lineDown count the columns in characters and not visible units. looks like there's a need for a function that counts the visible amount of columns from a given line.

apologies for not suggesting concrete code

[Miguel-hrvs]

I think that I mixed this issue with this one: #2330
You mean another thing right?