Is not there a way to change the time signature for an entire song? For some reason, I click on, let's say, measure 10 to make it 3/4. Measure 10 changes, but 11 and on are still 4/4. So I click on 11, change it to 3/4. Then, maybe a few measures will follow, but then, 4/4 shows up down the line again.
 
It must've been something I did when I made the original template.

I don't know which version of Sonar you're running and the way to get to the time signature screen is different for some versions of sonar.
 
but you need to change the time signature in the time signature window and not just insert a time signature change at a certain measure, but make sure that all time signatures after that measure do not have time signature changes in them as well.

I'm using Producer X3. Don't see any Time Signature window. There's an Events view, which shows the time signature. Looks like if I delete all but the first one, the problem goes away. Yep, looks like some old work I did on a song a few months ago. Somehow, when I saved it as a template, the TS remained with it.
 

Project > Insert Meter/Key Signature and Views > Meter/Key

If you have copy pasted clips in the project each of them includes a tempo and time signature definition of its own.

Yeah, I think that's what happened.

If I have a loop that is in 4/4 , but has one bar of 2/4, how can I reflect that in the Time Rular. I's set the first part, If I Copy and paste it, it becomes half a bar out. If I make the loop a Groove Clip and drag it out, it does the same.
 
Do I have to manually edit the Time Ruler manually throughout on a 3 minute song, or is there a mean to copy/drag the bars out?

Any ideas?

Scoot
If I have a loop that is in 4/4 , but has one bar of 2/4, how can I reflect that in the Time Rular. I's set the first part, If I Copy and paste it, it becomes half a bar out. If I make the loop a Groove Clip and drag it out, it does the same.
 
Do I have to manually edit the Time Ruler manually throughout on a 3 minute song, or is there a mean to copy/drag the bars out?

I don't think you can have a groove clip with mixed meters, because the "stretch+fill" action doesn't reproduce bar meter changes.
 
On the other hand, say you have a new project, and you set up the first three bars to be 4/4, 2/4, and 4/4, and you record your 3-bar clip. 
 
Now, if you select the clip, and go Edit > Copy Special, check the option for including time sig/meter changes and try pasting out into the future time line. I think the bar meter changes should also paste along with the clip copies. (I'm not at my studio PC, I can't verify this).