Hiding barlines

Early chants often had no barlines, so if you want to hide all of them right click any bar line, in the speed menu that pops up move your mouse over "select ->" click "all similar elements". V will toggle their hide status. You may have to use the join measures described above since you will probably have notes spanning measures. To remove the spurious ties, ESC to exit note entry mode if in it, click the note, press the number corresponding to the proper length of the note. Since the "allow notes to span measures" is indicated as experimental I would use the manual retiming of measures to avoid bugs. If you end up with some hidden and some visible bar lines simply select all the bar lines and press F8 to get the inspector up. Uncheck the square next to visible. If it is already unchecked click it 2 times, but not too fast.

Note: since the above comment was posted, Musescore has had some updates. You'll need to select the measures (bars), then go to Tools / Bar / Join Selected Bars. You might need to change some note durations (for example, turn a crotchet tied to a quaver to a dotted crotchet), because the software initially recognises the structure with barlines in, hence ties the note over the now non-existent (or non-visible, at any rate) bar.