Part swing, part straight

No

Hello jvuz, if by saying "a *part*" you mean a section of your composition, i.e. a few bars with everyone playing in swing 8th notes, followed by a few bars played in straight 8th notes, and change again in the following bars to swing 8th notes, the user DIM, has found a way to do this:

For this quite tricky workaround to create some quavers with swing feel to it. I will quote a post by DIM, (the original post can be found here:

Probably, you have to right click on each swung note individually
and change the ontime and offtime values ss suggestted by the user DIM in this post (see below)

http://musescore.org/en/node/9248#comment-94999

Subject: Ontime and offtime for 8'th note triplet feel

Posted by DIM on February 10, 2014 -8:05am
To make 8'th notes swing (in playback mode online) you can do the following. A quarter note is 100%. Two straight eight-notes is 50% each. But a swing-feel requires the first note to be around 2/3 and the latter 1/3. You can do it like this: Set the first 8'th note like this:

ontime offset type: offset
ontime offset: 0%
offtime offset type: offset
offtime: 66%

And the second 8'th like this:

ontime offset type: offset
ontime offset: 34%
offtime offset type: offset
offtime: -66%

It is very important to change the second 8'th note end-length to minus 66%, as the last triplet-feel 8'th note will "clip" the sound of the next-coming note in playback mode. It is a little tricky, but it works. .