UI fixes (#2727)

* ui fixes

- better coloring for scrollbar
- better styling for tooltip
- better styling for menuitem
- change max window size on startup to correctly display install tab

* Fix Borders of Right Click menu for Textbox (eg. Searchbar) (#9)

* sync fork & remove merge issues

* Revert "sync fork & remove merge issues"

This reverts commit dd64f06b89.

* remove unneeded code

---------

Co-authored-by: Martin Wiethan <47688561+Marterich@users.noreply.github.com>

config/themes.json

@@ -46,6 +46,9 @@
         "LabelBackgroundColor":  "#F7F7F7",
         "LinkForegroundColor":  "#232629",
         "LinkHoverForegroundColor":  "#232629",
+        "ScrollBarBackgroundColor": "#4A4D52",
+        "ScrollBarHoverColor": "#5A5D62",
+        "ScrollBarDraggingColor": "#6A6D72",
 
         "ProgressBarForegroundColor": "#2e77ff",
         "ProgressBarBackgroundColor": "Transparent",
@@ -77,6 +80,10 @@
         "LabelBackgroundColor":  "#121212",
         "LinkForegroundColor":  "#add8e6",
         "LinkHoverForegroundColor":  "#F7F7F7",
+        "ScrollBarBackgroundColor": "#2E3135",
+        "ScrollBarHoverColor": "#3B4252",
+        "ScrollBarDraggingColor": "#5E81AC",
+
         "ProgressBarForegroundColor": "#222222",
         "ProgressBarBackgroundColor": "Transparent",
         "ProgressBarTextColor": "#cccccc",