Created attachment 170314 [details] A screenshot of the issue SUMMARY Transparent backgrounds blend with the previously rendered frame instead of blending with what's behind the window. STEPS TO REPRODUCE 1. Go to Settings -> Configure Kate -> Color Themes -> Theme Editor 2. Select an editable theme to edit, or make a new one by using the "copy" feature. 3. In "Editor Background Colors", edit the "Text Area" color to have an alpha channel value below 255. 4. Exit out of the settings, and apply the theme you created/edited through Settings -> Editor Color Theme. OBSERVED RESULT What is in the included screenshot is observed. I wrote a line of "a" on line 13, with other empty lines around. The rest of the faded copies are from previous frames; I had scrolled down to make this image, so line 13 was further down previously. The alpha value of the Text Area color is 160 in this screenshot. EXPECTED RESULT The background should show the desktop behind Kate, blended with the "Text Area" color, or Kate should ignore the alpha channel/prevent the user from setting the alpha channel below 255 if transparency is not intended to be supported. SOFTWARE/OS VERSIONS Linux/KDE Plasma: 6.5.0-28 KDE Plasma Version: 6.0.4 KDE Frameworks Version: 6.2.0 Qt Version: 6.7.0 ADDITIONAL INFORMATION This is a regression from Plasma 5, where it blended with what is behind the window correctly, using the same editor theme I am now using. This happens in both Kate and KWrite.
Sorry this is not supported. It would require a huge, gigantic rewrite of the text rendering. Unless we get a credible effort by somebody from outside the current active developer team, to re-implement the text rendering, this is not something that is likely to happen any time soon. Kate has just a small handful of active developers. Sorry, BR, Kåre