Change the default canvas name from "Canvas 1" to "Canvas_1", solving the following issue: When saving the canvas as C++ script, it uses the canvas name as object name, creating a non-working C++ script.
Close the browser before terminating the application

Fix a rounding problem in TGListBox when the entries have different height. This solves a problem with TGFontTypeComboBox, the last item (the one that reads "13. times") was barely visible. Only the top 2 or 3 pixels could be seen when the vertical scrollbar is at its lowest possible position.

Added a new fStyle data member and the getter/setter methods (GetStyle()/SetStyle()), allowing to select between classic (win95) and modern (e.g. flat popup menu and toolbar buttons) look. This can be enabled/disabled via the new option GUI.Style in $ROOTSYS/etc/system.rootrc, the default being set as modern

Properly position (center) the pictures when using different font size (part of the task #18792)
Create a new (flat) style for some buttons (e.g. the toolbar buttons) and added the SetStyle() method

Enable the new (flat) button style. This can be enabled/disabled via the GUI.Style entry in $ROOTSYS/etc/system.rootrc (or in a user defined $HOME/.rootrc)

Add a new (modern) way of displaying the popup menus (flat frame with gray border). This can be selected/changed via the "Gui.Style" entry in the system.rootrc file (modern being the default)

Create a new (flat) style for scrollbars. This is enabled/disabled via the GUI.Style entry in $ROOTSYS/etc/system.rootrc (or in a user defined $HOME/.rootrc)

Change the way the current (selected) item is highlighted (full width instead of text only)

Change the way the current (selected) item and the item below the mouse are highlighted (full width instead of text only)
Slightly improve search on Linux (implemented F3, Ctrl+F and Ctrl+G) and make it working on Windows

Fix a problem when browsing geometries (TGeoManager must not be treated as a regular TDirectory)
Allow user to specify any custom filter (e.g. *.png) in the filter combo box
Enable the new (flat) button style. This can be enabled/disabled via the GUI.Style entry in $ROOTSYS/etc/system.rootrc (or in a user defined $HOME/.rootrc)
Create special icons for symlinks (shortcuts) in the browser (add a small arrow on bottom left corner of the original icon)

Implemented the wish #78935: Longer "File of type:" selector is wanted (make more combo box entries visible)
Enable the new (flat) button style. This can be enabled/disabled via the GUI.Style entry in $ROOTSYS/etc/system.rootrc (or in a user defined $HOME/.rootrc)

Added a "Close" menu entry
Properly ask the user to save the currently opened file (if modified) when trying to open a new file
Moved the IsSaved() part of the code in the LoadFile() method, to make sure it works also when the text editor is used as a plugin in the browser
Change the text highlighing color
Cleanup the text when quitting root (avoid potential crash on Linux)

Allow to override CTRL+S behavior by using the TGMainFrame::BindKey() function

Renamed TVirtualDragManager::GetDragType() to TVirtualDragManager::GetEDragType(), to avoid potential clash between two classes (TGFrame and TVirtualDragManager) having both GetDragType method with different return types. And they are both inherited by one class (TGuiBldDragManager) which doesn't define GetDragType.

Properly set the text color of the tooltip label, using the value of Gui.TooltipForegroundColor in $ROOTSYS/etc/system.rootrc (or in a user defined $HOME/.rootrc)

Only add non-empty strings (urls) in the combo box, to avoid empty entries
Enable the new (flat) button style. This can be enabled/disabled via the GUI.Style entry in $ROOTSYS/etc/system.rootrc (or in a user defined $HOME/.rootrc)