For some reason, the "(i) comparison" icon is displayed too big. This icon affects the toolbar height, and when switching between tabs, the toolbar height changes depending on the visibility of that icon. As a consequence, mouse clicks on a tab can trigger toolbar buttons and lead to unintended operation.
The icon issue happens in some other GTK apps as well. Possibly the "(i)" icon is only available in a different resolution or file format than the others. In any case it should display in a uniform size. Either this is a bug in GTK or the icon is incorrectly setup by the application.
This happens on a high-dpi display (aka system settings UI scale slider at 2.0).
ProblemType: Bug
DistroRelease: Ubuntu 16.10
Package: meld 3.16.3-1
ProcVersionSignature: Ubuntu 4.8.0-27.29-generic 4.8.1
Uname: Linux 4.8.0-27-generic x86_64
ApportVersion: 2.20.3-0ubuntu8
Architecture: amd64
CurrentDesktop: Unity
Date: Wed Nov 16 19:03:50 2016
EcryptfsInUse: Yes
InstallationDate: Installed on 2016-11-05 (11 days ago)
InstallationMedia: Ubuntu 16.10 "Yakkety Yak" - Release amd64 (20161012.2)
PackageArchitecture: all
SourcePackage: meld
UpgradeStatus: No upgrade log present (probably fresh install)
We are sorry that we do not always have the capacity to review all reported bugs in a timely manner.
This release of Ubuntu is no longer receiving maintenance updates. If this is still an issue using a maintained version of Ubuntu then please let us know otherwise this report can be left to expire in approximately 60 days time.
Paul White
[Ubuntu Bug Squad]