Having two or more Editor Tabs for the same connection, and opening the EXPLAIN PLAN Tab on at least two of those Tabs, when one tries to compare the PLANs, it's impossible.
For example, if a line is highlighted in a Tab's PLAN, and one goes to another Tab's PLAN to highlight another line, when one comes back to the initial Tab, the highlighted line changed, meaning, is no longer highlighted, instead, what Toad's highlighting is the always the first line of the Tab's PLAN.
And like this, other things change, here's a list:
1. - Column's Size.
2. - Column's Value-Type: Integer, char, ...
3. - Columns Order.
4. - Highlighted Row.