Splitting a bar

What I (and, I'm sure, other) do is in practice making two measures instead of the one which should be splitted.

For the sake of the example; I'll assume the time is 4/4, the measure before the repeat is only 3/4 long and the next section (if any) will begine with an anacrusis measure of 1/4. Then:

1) Right-click the measure you want to end with the repeat and select "Measure Properties" (if this item does not show up in the pop menu, you have right clicked something else: be sure to click on an empty spot of the measure, away enough from any note, stem, beam, ... in the measure itself)

2) In the dlg box, modify the "Measure duration | Actual" values, which should show 4 / 4, into 3 / 4 and press OK: the measure will be shortened to contain only 3 quarters.

3) Add the repeat bar line in the usual way

4) If you need, repeat for the following measure, set its "Measure duration | Actual" to 1 / 4 and press OK.

Note: any notes which were in the measure duration you 'cut away' is lost: this is expected. So, it is usually better to modify the measure duration before filling them.

If you have already entered the full measure and need to 'split' it into two, do as follow:

1) Select the measure after the measure to split
2) Menu command "Create | Measure | Insert measure": a new, empty measure is created before the selected one.
3) Shorted the measure to split as described above (to 3/4 according to our example)
4) Shorten the following measure -- currently empty -- (to 1/4 according to our example)
5) Fill this measure with the music (1/4) which no longer fits in the previous measure.

HTH,

M.

If you don't want to get technical or fancy, are not overly concerned with the playback and just want the appearance of a bar line in the middle of a measure - click on a note, double-click on a barline and the line gets placed before the note you just clicked on.